Thermal management device and system

ABSTRACT

Thermal management systems comprising a thermoelectric component, a two-phase heat transfer unit, and a controller. The heat transfer unit has a phase-transition chamber and microfeatures in the phase-transition chamber that induce capillary forces to a working fluid that drives the working fluid through the phase-transition chamber. The controller is configured to operate the thermoelectric component and the heat transfer unit such that the heat transfer unit cools one side of the thermoelectric component to a first temperature and the thermoelectric component changes the temperature of a target material on its other side to a second temperature of +/−60° C. of the first temperature within 0.5-20 seconds.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of U.S. ProvisionalApplication 62/877,122, filed 22 Jul. 2090, and U.S. ProvisionalApplication 62/954,759, filed 30 Dec. 2019, which are both incorporatedherein by reference in their entirety.

FIELD OF THE INVENTION

The present technology relates to a device for cooling and heating atarget material, such as tissue, a heat source, or another type ofsubstrate.

BACKGROUND OF THE INVENTION

Many electronic devices, medical and aesthetic devices, and high heatflux systems use thermal management devices to operate within acceptabletemperature ranges and/or achieve desired outcomes. In manyapplications, the thermal management systems extract and dissipate heatfluxes to maintain temperatures within acceptable ranges for the targetmaterial.

One type of thermal management system is a two-phase heat transferdevice in which a working fluid transitions from liquid phase to vaporphase to extract heat from the target material. In such two-phase heattransfer devices, high heat transfer rates can be obtained because ofthe latent heat of evaporation of the working fluid. Two-phase heattransfer devices have been disclosed for use in cooling semiconductordevices (e.g., controllers, memory devices, etc.), computer systems(e.g., servers), medical devices used in tissue, hair, adipose and painmanagement treatments, and wearable cooling devices.

Semiconductor devices, such as controllers, memory devices and lightemitting diodes, often need to dissipate heat for maintaining acceptableoperating temperatures. As the speeds and capacities of these devicesincrease, the heat fluxes increase requiring more heat to be dissipatedto maintain acceptable operating temperatures. However, in manyapplications the heat fluxes of high-performance semiconductor devicesand computing systems are too high for the heat transfer systems, and asa result the speeds and capacities of the systems are limited. Thisproblem is only exacerbated as mobile phones, tablets and laptopcomputers have smaller sizes and/or higher performance. Similarly,large-scale server applications in which many servers are housed in acommon location (e.g., data storage, web systems and computing centers)have significant heat dissipation requirements. Although two-phase heattransfer systems have high heat transfer rates, they are often too largeand cumbersome for use with semiconductor devices and high-performancecomputing systems.

Several medical and aesthetic procedures heat and/or cool tissue toreduce pain, manage swelling, reduce adipose tissue for body sculpting,remove hair, tighten skin (e.g., remove wrinkles), remove lesions, altersebaceous glands, and other heat treatments. The tissue can be heatedusing radiofrequency energy, laser energy, ultrasonic energy, X-rayradiation beams, and other energy modalities. For example, hyperthermiamethods use heat to damage cancer cells for treating cancer (see, e.g.,U.S. Pat. No. 9,802,063). Other medical applications treat conditions bycooling tissue, such as cryogenic tissue remodeling (see, e.g., U.S.Pat. No. 10,363,080).

One challenge of heating and/or cooling tissue is accurately controllingthe temperature of the target tissue because different types of tissuereact differently to heat and cooling, and different depths within thetissue can react differently because blood flow can significantly impactthe temperature of the target site. Another challenge is unwantedheating and cooling of adjacent tissues, such as nerves or epidermaltissue. Although two-phase heat transfer systems have been used forthermal management of target tissue in medical and aestheticapplications, conventional systems often have slow response times andtherefore do not provide precise thermal modulation of a target tissue.Additionally, many medical and aesthetic applications use bulky heattransfer devices that are uncomfortable for the patient and impracticalfor home use or treating certain body parts (e.g., the face, knees,shoulders, ankles, wrists, etc.).

Devices for cooling a target material or substrate are known. See forexample U.S. Pat. No. 10,217,692. Methods for cooling skin inconjunction with skin treatment are also known. See Nelson J S, MajaronB, Kelly K M., Active Skin Cooling in Conjunction with LaserDermatologic Surgery, Semin Cutan Med Surg. 2000; 19:253-66 and Das etal., J. Cutan. Aesthet. Surg. 2016; 9(4): 215-219.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C are isometric views of a thermal management system forcooling and/or heating a target material in accordance with embodimentsof the present technology.

FIG. 2 is a graph of time and temperature of a surface of a targetmaterial simulating human tissue using a thermal management system inaccordance with the present technology.

FIG. 3 is a graph of time and temperatures of a surface and withinvarious depths of a target material simulating human tissue using athermal management system in accordance with the present technology.

FIG. 4 is a graph of time and temperature of another application ofusing a thermal management system in accordance with the presenttechnology.

FIG. 5 is a graph of time and energy of a heat flux associated with athermal management system in accordance with the present technology.

FIG. 6 is a schematic cross-sectional view of a thermal managementsystem in accordance with the present technology.

FIG. 7 is an isometric view of using the thermal management system ofFIG. 6 in accordance with the present technology.

FIG. 8A is a schematic side view and FIG. 8B is a schematic top view ofa thermal management system in accordance with the present technology.

FIG. 9 is a schematic top view of a thermal management system inaccordance with the present technology.

FIG. 10 is a schematic top view of a device with a thermal managementsystem in accordance with the present technology.

FIG. 11 is a schematic top view of a device with a thermal managementsystem in accordance with the present technology.

FIG. 12 is a schematic cross-sectional view of a semiconductor devicewith a thermal management system in accordance with the presenttechnology.

FIG. 13 is a schematic cross-sectional view of a semiconductor devicewith a thermal management system in accordance with the presenttechnology.

FIG. 14 is a schematic view of an assembly of electronic devices, suchas servers, with thermal management systems in accordance with thepresent technology.

FIG. 15A schematically illustrates an embodiment a heat transfer unitfor use with thermal management systems of the present technology. FIG.15B is an enlarged partial view of a single passage in the device ofFIG. 15A. FIG. 15C is an enlarged partial view of the thin film regionas part of the meniscus as shown in FIG. 15B where the bulk ofevaporation and heat transfer take place. FIG. 15D is a block diagram ofthe general arrangement of the device of FIG. 15A. FIG. 15Eschematically illustrates the general circuit of the heat flow travelingwithin an embodiment of the heat transfer device.

FIG. 16A schematically illustrates an embodiment of a phase change heattransfer device with continuous, ordered evaporation without disruptionfrom boiling and/or dry-out. FIGS. 16B is an enlarged partial view of apassage shown in FIG. 16A showing the vapor space and the dimensions ofthe passage. FIG. 16C schematically illustrates another embodiment of aphase change heat transfer device in operation with continuous, orderedevaporation without disruption from boiling and/or dry-out. FIG. 16D isan enlarged partial view of a passage shown in FIG. 16C showing thevapor space and the dimensions of the passage.

FIG. 17A schematically illustrates an embodiment of a microfeature incontact with the working fluid and illustrates the associated wettingand non-wetting coatings of the embodiment. FIG. 17B schematicallyillustrates an embodiment of a microfeature in contact with the workingfluid and illustrates an embodiment with a wick.

FIG. 18A schematically illustrates a radial arrangement of microfeaturesand the corresponding widening passages to accommodate the vaporpathways. FIG. 18B schematically illustrates a parallel arrangement ofan embodiment of microfeatures and the corresponding passages toaccommodate the vapor pathways. FIG. 18C schematically illustratesanother embodiment of the radial arrangement with discontinuous wall orpanel shaped microfeatures (panels, walls, pins, posts, or rods orsimilar shaped structures) to define various passages to accommodate thevapor pathways. FIG. 18D schematically illustrates another embodiment ofa radial arrangement of microfeatures with rods, pins, or post-shapedelongated members (or similar structure, or discontinuous wall or panelor similar shaped structures). FIG. 18E schematically illustrates aparallel arrangement of microfeatures with elongated members ofdifferent lengths placed to allow the passages (e.g., channels or otherstructures) to widen in the pathway of vapor flow.

FIGS. 19A-19D schematically illustrate various embodiments ofmicrofeatures in the form of a wall or panel having a variety ofcontours or shapes, and which may have multiple curves or angles. Someshapes may include multiple contours (FIG. 19A); multiple angles (FIG.19B); single curve (FIG. 19C); and straight alignment (FIG. 19D).

FIGS. 20A-20E schematically illustrate various embodiments ofmicrofeatures in the shape of a rod, pin, or post having differentcross-sections as follows: circular, oval, rectangular (or square),hexagonal, and triangular, respectively. The cross section may be of anypolygonal cross section.

FIGS. 21A-21C are schematic views of a non-invasive temperaturemonitoring system for determining the temperature gradient within atarget material (e.g., mammalian tissue) for use with any of theforegoing thermal management systems described with respect to FIGS.1A-20E herein and/or any of the energy-based treatment systems describedherein (e.g., subcutaneous adipose tissue reduction, laser treatments,and radiation beam treatments).

FIGS. 22 and 23 are schematic views of a non-invasive temperaturemonitoring system for determining the temperature gradient within atarget material (e.g., mammalian tissue) for use with any of theforegoing thermal management systems described with respect to FIGS.1A-20E herein and/or any of the energy-based treatment systems describedherein (e.g., subcutaneous adipose tissue reduction, laser treatments,and radiation beam treatments).

FIG. 24 is a schematic view of a non-invasive temperature monitoringsystem for determining the temperature gradient within a target material(e.g., mammalian tissue) for use with any of the foregoing thermalmanagement systems described with respect to FIGS. 1A-20E herein and/orany of the energy-based treatment systems described herein (e.g.,subcutaneous adipose tissue reduction, laser treatments, and radiationbeam treatments).

FIG. 25 is a schematic view of a non-invasive temperature monitoringsystem for determining the temperature gradient within a target material(e.g., mammalian tissue) for use with any of the foregoing thermalmanagement systems described with respect to FIGS. 1A-20E herein and/orany of the energy-based treatment systems described herein (e.g.,subcutaneous adipose tissue reduction, laser treatments, and radiationbeam treatments).

FIG. 26 is a schematic view of a non-invasive temperature monitoringsystem for determining the temperature gradient within a target material(e.g., mammalian tissue) for use with any of the foregoing thermalmanagement systems described with respect to FIGS. 1A-20E herein and/orany of the energy-based treatment systems described herein (e.g.,subcutaneous adipose tissue reduction, laser treatments, and radiationbeam treatments).

FIG. 27 is a schematic view of a non-invasive temperature monitoringsystem for determining the temperature gradient within a target material(e.g., mammalian tissue) for use with any of the foregoing thermalmanagement systems described with respect to FIGS. 1A-20E herein and/orany of the energy-based treatment systems described herein (e.g.,subcutaneous adipose tissue reduction, laser treatments, and radiationbeam treatments).

FIG. 28 is a schematic view of a non-invasive temperature monitoringsystem for determining the temperature gradient within a target material(e.g., mammalian tissue) for use with any of the foregoing thermalmanagement systems described with respect to FIGS. 1A-20E herein and/orany of the energy-based treatment systems described herein (e.g.,subcutaneous adipose tissue reduction, laser treatments, and radiationbeam treatments).

The figures should be understood to present illustrations of embodimentsof the invention and/or principles involved. As would be apparent to oneof skill in the art having knowledge of the present technology, otherdevices, methods, and particularly equipment used in heat transferdevices, temperature sensors, microfeatures, and/or thermoelectriccomponents, will have configurations and components determined, in part,by their specific use. Like reference numerals refer to correspondingparts throughout the several views of the drawings.

DETAILED DESCRIPTION OF EMBODIMENTS

Aspects of the present technology are directed to systems for regulatingthe temperature of a target material (e.g., substrate), such asmammalian tissue (e.g., human tissue) and electronic devices. It will beappreciated that devices in accordance with the present technology cancontrol the temperature of the surface of the substrate and/or regulatethe temperature at a depth within the substrate. According to oneaspect, the systems for regulating the temperature of a substrateinclude a heat-transfer unit operatively connected to a thermoelectriccomponent for heating or cooling a substrate surface.

The present technology can be used in high heat flux applications, suchas treatment of mammalian tissue (used interchangeably with human tissuethroughout), computer chips, semiconductor devices, integrated circuitdevices, laser systems (e.g., high power laser systems with high heatfluxes that need to be dissipated to generate desired output beamsand/or power), skin of hypersonic flying objects, parabolic solarcollectors, high performance computing systems, radio frequency (RF)systems, photovoltaic or concentrated photovoltaic systems, hypersonicavionic applications, turbine blades, or any other surfaces orvolumetric heat dissipation devices or systems. The thermal managementsystems of the present technology are particularly efficacious forcooling the skin of a patient with respect to treatments using laserlight or needles. For example, cooling the epidermis and dermis toreduce pain when the tissue is treated with a laser light or a needle.It should be appreciated that various embodiments of the presenttechnology device may be applied to and/or be utilized with a wide rangeof applications as desired, needed or required.

FIGS. 1A-1C are isometric views of a thermal management system 100 forcooling and/or heating a target material 101 in accordance withembodiments of the present technology. The thermal management system 100can accurately and quickly control the temperature at the surface of thetarget material 101 and/or at a depth within the target material 101. Asdescribed in more detail below, the target material 101 can be mammaliantissue (e.g., skin, adipose tissue, hair, lesions, cancerous cells,etc., of a human), semiconductor devices (e.g., controllers, memorydevices, light emitting diodes, servers, high-performance computers,etc.), and other applications with high heat fluxes (e.g., lasers).

Referring to FIGS. 1A and 1B together, the thermal management system 100can include an optional contact member 110, at least one thermoelectriccomponent (TEC) 120 a (FIG. 1B) thermally coupled to the contact member110, and a two-phase heat transfer unit 140 thermally coupled to the TEC120 a. FIG. 1A shows the thermal management system 100 fully assembled,and FIG. 1B shows the thermal management system 100 without the heattransfer unit 140. The thermal management system 100 can have severalTECs, for example first, second and third TECs 120 a-c, respectively(referred to collectively throughout as TECs 120). The thermalmanagement system 100 can have any number of TECs 120 and is not limitedto having three TECs 120. The thermal management system 100 can alsoinclude a condenser 180 operatively coupled to the heat transfer unit140 to form a closed system and a controller 190 operatively coupled tothe TECs 120, the heat transfer unit 140 and/or the condenser 180. Inoperation, a working fluid contained in the heat transfer unit 140 andthe condenser 180 changes from a liquid phase to a vapor phase in theheat transfer unit 140 to cool one side of the TECs 120, and thecontroller 190 adjusts an electrical current through the TECs 120 and/orthe flow of working fluid through the heat transfer unit 140 to managethe temperature of the contact member 110 and thus the target material101.

In the assembled state shown in FIG. 1A, the contact member 110, TECs120 and heat transfer unit 140 can be held together by bolts 199. TheTECs 120 can further be attached to the contact member 110 by a firstthermal interface material and to the underside of the heat transferunit 140 by a second thermal interface material. The heat managementsystem 100 can have any suitable length L and width W for covering adesired area of the target material 101. The heat management system 100can have a low-profile with a height H of 2 mm-25 mm, including 5 mm, 10mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20mm, 21 mm, 22 mm, 23 mm, 24 mm and 25 mm. The heat transfer unit 140itself can have a thickness T of 2 mm-20 mm, including 3 mm, 4 mm, 5 mm,6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm,17 mm, 18 mm and 19 mm. For example, when the heat transfer unit 140 isdirectly integrated into the second portion 122 b of a TEC 120, theoverall height H can be 2-3 mm. The height H and thickness T can bemeasured in a direction of heat flow through the TECs 120 (arrow HF inFIG. 1B).

The TECs 120 each have a first portion 122 a and a second portion 122 b.The first and second portions 122 a-b are understood relative topositioning with respect to the surface of the target material 101, inwhich the first portion 122 a is thermally coupled to the targetmaterial 101 and the second portion 122 b is opposite the first portion122 a. The first portion 122 a of the TECs 120 can include a first outersurface 124 a (i.e., the lower surface in FIG. 1B) of the TECs 120 and aportion of the TECs 120 that extends inwardly a distance from the firstouter surface 124 a. The second portion 124 b of the TECs 120 caninclude a second outer surface 124 b (i.e., the upper surface in FIG.1B) of the TECs 120 and a portion of the TECs 120 that extends inwardlya distance into the interior of the TECs 120 from the second outersurface 124 b. It is to be understood that the TECs 120 may have amidpoint equidistant within the interior of the TECs 120 between thefirst and second outer surfaces 124 a-b. The first and second portions122 a-b of the TECs 120 are electrically connected to a power source.For example, the TECs 120 may each include a first electrical contact126 a (shown in phantom line) at the first portion 122 a and a secondelectrical contact 126 b at the second portion 122 b through which anelectrical current can flow in either direction.

The first portion 122 a of the TECs 120 is intended to be thermallycoupled to a surface of the target material 101 either directly orindirectly. For example, the first portion 122 a of the TECs 120 can beindirectly thermally coupled to the target material 101 via the contactmember 110, which can be a plate, panel, film or fabric made from amaterial with a high thermal conductivity (e.g., an aluminum plate orpanel). The heat management system 100 may include two or more suchplates or panels or films contacting each other as desired. The secondportion 122 b of the TECs 120 is thermally coupled to the heat transferunit 140 either directly or indirectly. For example, the second portion122 b of the TECs 120 is directly coupled to the heat transfer unit 140by a thermal interface material having a high thermal conductivity. Theheat transfer unit 140 can remove heat from the target material 101 aswell as heat generated by the TECs 120.

Without wishing to be bound by scientific theory, heat flow is inducedin a certain direction in the TECs 120 by electric current. According toone nonlimiting aspect, when the device for regulating the temperatureof the target material 101 is activated and electricity flows in adirection from the second portion 122 b of the TECs 120 to the firstportion 122 a of the TECs 120, the first portion 122 a cools relative toits ambient or starting temperature, i.e., the temperature of the firstportion 122 a decreases thereby removing heat from the target material101. The second portion 122 b accordingly heats or generates heatrelative to its ambient or starting temperature. It is to be understoodthat embodiments are contemplated where the direction of heat flow maybe in the same direction as electric current flow or in the oppositedirection of the electric current flow.

The heat-transfer unit 140 may be fixed to the second portions 122 b ofthe TECs 120 or it may be selectively detached from the second portions122 b of the TECs 120 to break the thermal contact with the TECs 120using piezoelectric drivers, electric motors or other electromechanicaldevices. Similarly, the TECs 120 may be selectively detached from (i.e.,separated from) the target material 101 and or the contact member 110 tobreak thermal contact therewith using piezoelectric drivers, electricmotors or other electromechanical drivers. Such devices may be known asthermal switches insofar as heat is used to cause the switch to altershape creating physical separation between two surfaces (e.g., an airgap), such as the two-phase heat-transfer unit 140 and the TECs 120 orthe TECs 120 and the contact member 110. According to one aspect, it maybe desirable to disconnect the heat transfer unit 140 from the TECs 120or to disconnect the TECs 120 from the contact member 110 for a givenperiod of time.

Referring to FIGS. 1A and 1B, the heat transfer unit 140 covers thesecond portions 122 b of the TECs 120. The heat transfer unit 140 has aninlet 142, an outlet 144, and a cover 146. In operation, a working fluidflows in a liquid state or a mixed liquid-vapor state (e.g., highpressure single-stage closed cooling systems) from the condenser 180 tothe inlet 142, and at least a portion of the working fluid flows in avapor state from the outlet 144 back to the condenser 180. The cover 146retains the working fluid within the heat transfer unit 140 and alongwith other components defines the flow characteristics of the workingfluid through the heat transfer unit 140.

FIG. 1C illustrates embodiments of the internal structure of the heattransfer unit 140 with the cover 146 (FIG. 1B) removed. The heattransfer unit 140 can include a base 148 to which the cover 146 isconnected, at least one phase-transition chamber 150 (threephase-transition chambers 150 a-c shown and identified individually),and a duct system 160 fluidically coupled to the inlet 142, the outlet144, and the phase-transition chambers 150 a-c. The phase-transitionchambers 150 a-c are at least generally aligned with a corresponding oneof the TECs 120 a-c, respectively. For example, each of thephase-transition chambers 150 a-c can be directly superimposed above acorresponding one of the TECs 120 a-c, respectively. The heat transferunit 140 can have a single inlet 142 and single outlet 144 to serviceall of the phase-transition chambers 150 a-c as shown, or the heattransfer unit 140 can have several inlets 142 and outlets 144. Forexample, the heat transfer unit 140 can have one or more inlets 142and/or outlets 144 for each phase-transition chamber 150 a-c or for anyother purpose to provide the desired flow of working fluid through theheat transfer unit 140.

The phase-transition chambers 150 a-c include microfeatures 152, aninlet region 154, and an outlet region 156. The microfeatures 152 shownin FIG. 1C are pins or posts arranged in a grid-type array, but in otherembodiments the microfeatures can be elongated walls. The microfeatures152 define microchannels 153 through which the working fluid flowsthrough the phase-transition chambers 150 a-c. The microfeatures 152,whether pins or elongated walls, can have different arrangements otherthan a being arranged in straight, uniform rows as described below withreference to FIGS. 18A, 18C and 18D. The microfeatures 152 can be spacedapart from each other by a uniform distance, or the distance betweenmicrofeatures 152 can vary in relation to the positions and flowcharacteristics of the inlet region 154 and the outlet region 156. Forexample, the microfeatures 152 can be spaced apart from each other by afirst distance in the inlet region 154 and a second distance in theoutlet region 156. The second distance can be greater than the firstdistance to accommodate the flow of vapor through the outlet region 156,or the second distance can be less than the first distance toaccommodate the capillary force exerted against the liquid phase of theworking fluid flowing through the phase-transition chambers 150 a-c.Additionally, the spacing between microfeatures 152 in one of thephase-transition chambers 150 may be the same as or different than thespacing between microfeatures 152 in one or more of the otherphase-transition chambers 150 a-c.

The spacing between the microfeatures 152 can be selected to (a)generate capillary forces in the working fluid that drives the workingfluid from the inlet region 154 of the phase-transition chamber to theoutlet region 156, (b) accommodates the flow of vapor through the inletand outlet regions 154 and 156 of the phase-transition chambers 150 a-c,and/or (c) forms a desired meniscus between adjacent microfeatures 152to enhance the evaporation zone along each microfeature 152 to enhanceheat transfer. In some embodiments, the spacing between microfeatures isselected such that the capillary forces induced in the working fluidenable the heat transfer unit 140 to operate omnidirectionally (e.g.,inverted so the heat transfer unit 140 is below the TECs or at an anglerelative to horizontal). The spacing between microfeatures 152, forexample, can be a range having a low end of 50 nm, 100 nm, 200 nm, 500nm, 1 μm, 2 μm, 5 μm or 10 μm and a high end of 25 μm, 50 μm, 100 μm,150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 600 μm,700 μm, 800 μm, 900 μm or 1,000 μm. In specific examples, the spacingbetween microfeatures can be 100 nm-1,000 μm, 100 nm-500 μm, 100 nm-400μm, 100 nm-300 μm, 100 nm-250 μm, 100 nm-200 μm, 50 nm-150 μm, 50 nm-100μm, 50 nm-50 μm, 50 nm-25 μm or 50 nm to 10 μm.

The duct system 160 includes a primary duct 162 having a first channel163 a fluidically coupled to the inlet 140 and a second channel 163bextending from the first channel 163 a along the phase-transitionschambers 150 a-c. The duct system 160 further includes manifold ducts164 a-c (referred to collectively as “manifold ducts 164”) and an exitduct 166. The manifold ducts 164 are fluidically coupled to the secondchannel 163 b of the primary duct 162 at junctions 165, and the exitduct 166 is fluidically coupled to the outlet 144. The phase-transitionchambers 150 a-c can further include inlet ports 167 and outlet ports168. The inlet ports fluidically couple the respective manifold ducts164 to the inlet regions 154 of the phase-transition chambers 150 a-c,and the outlet ports 168 fluidically couple the outlet regions of thephase-transition chambers 150 a-c to the exit duct 166. The inlets ports167 can be small passages having a uniform arrangement along therespective manifold ducts 164 a-c (only shown along manifold duct 164 afor convenience, but also present along manifold ducts 164 b and 164 c).The outlet ports 168 can be larger passages at the end of the outletregions 156 of the phase-transition chambers 150 a-c through which vaporpasses into exit duct 166. The outlet ports 168 can be arrangeddifferently for different phase-transition chambers 150 a-c to providethe desired flow of vapor along the exit duct 166. For example, in theillustrated embodiment the outlet ports 168 of the firstphase-transition chamber 150 a can be at an upstream portion of the exitduct 166 relative to the first phase-transition chamber 150 a, theoutlet ports 168 of the second phase-transition chamber 150 b can be ata middle-stream portion of the exit duct 166 relative to the secondphase-transition chamber 150 b, and the outlet ports 168 of the thirdphase-transition chamber 150 c can be a downstream region of the exitduct 166 relative to the third phase-transition chamber 150 c.

In operation, the working fluid flows from the condenser 180 (FIG. 1A)to the inlet 140 in the liquid phase, and then the working fluid flowsthrough the primary duct 162 and the manifold ducts 164 a-c to the inletports 167. The manifold ducts 164 a-c and the junctions 165 can beconfigured to provide a uniform distribution (e.g., uniform flow) of theworking fluid to the inlet ports 167 along the phase-transition chambers150 a-c. The working fluid then flows through the inlet ports 167, themicrochannels 153 of the individual phase-transitions chambers 150 a-c,and the outlet ports 168 in flows F1, F2 and F3. As the working fluidflows through the phase-transition chambers 150 a-c, it transitions fromliquid phase to vapor phase in the evaporation regions along themicrofeatures 152.

The base 148 of the heat-transfer unit 140 can be made from aluminum,copper, silicon, or other materials with high thermal conductivity. Thephase-transition chambers 150 a-c, microfeatures 152, and duct system160 can be formed by masking and etching the base as known insemiconductor manufacturing, waterjet cutting, laser ablation, or bythree-dimensional printing. Additionally, the surface of the base 148 inthe phase-transition chambers 150 a-c can be texturized, such as bysandblasting.

The heat-transfer unit 140 removes heat from the second portions 122 bof the TECs 120 whether generated by electricity flowing through theTECs 120 or from the target material 101 itself (e.g., when the targetmaterial is an active heat source such as a controller, memory device,laser, etc.). Since the TECs 120 may generate a high heat flux, theheat-transfer unit 140 should remove (e.g., dissipate) at least aportion of the high heat flux. In this manner, the TECs 120 maycontinually cool the target material, i.e. continually remove heat fromthe target material. The heat-transfer unit 140 can prevent or otherwiselimit the TECs 120 from overheating during use. If the heat-transferunit 140 were not used, then heat generated at the second portions 122 bof the TECs 120 would gradually increase thereby decreasing the abilityof the TECs 120 to cool the target material. The heat-transfer unit 140is selected such that it has the ability to remove sufficient heatgenerated at the second portion 122 b of the TECs 120 to allow the firstportions 122 a of the TECs 120 to cool the target material, as desired.

The TECs 120 may maintain the target material 101 at a constanttemperature or may lower and/or raise the temperature of the targetmaterial 101 according to a desired temperature profile. One or moreauxiliary heating or cooling elements in addition to the TECs 120 may bepositioned adjacent the target material 101 so as to provide auxiliaryheating or cooling of the target material 101. For example, the TECs 120may be used to cool the target material surface and a separate resistiveheating element may be used to heat the target material surface.Additionally, the TECs 120 may be used to heat the target materialsurface and an auxiliary cooling element may be used to cool the targetmaterial surface.

According to one aspect, the TECs 120 may be used to heat or otherwiseincrease the temperature of the target material 101. For example, whenthe thermal management system 100 is activated and electricity flowsthrough the TECs 120 such that the first portion 122 a of the TECs 120heats or generates heat relative to its ambient or starting temperature,i.e., the temperature of the first portion 122 a of the TECs increaseswhile the second portion 122 b of the TECs 120 cools relative to itsambient or starting temperature. In this manner, the temperature of thetarget material may be increased relative to its ambient temperature. Itis to be understood that embodiments of semiconductors materials orarrangements of semiconductor materials of the TECs 120 can beconfigured such that the direction of heat flow may be in the samedirection as electric current flow or in the opposite direction of theelectric current flow. When used in this operating mode to heat a targetmaterial, the heat-transfer unit 140 may be deactivated or physicallyseparated from the TECs 120 such that the heat-transfer unit 140 doesnot remove heat from the cold side of the TECs 120. However, theheat-transfer unit 140 and the TECs 120 may alternatively be operatedconcurrently to achieve a desired temperature profile of the targetmaterial even when the TECs 120 are warmer at the first portion 122 athan at the second portion 122 b, including lowering the temperaturefrom an ambient or starting temperature and then raising thetemperature.

The TECs 120 may lower or raise the temperature of the target materialaccording to a desired temperature profile depending upon the directionof flow of the electric current through the TECs 120. According to oneaspect of the present technology, the TECs may be used to decreaseand/or increase the temperature of the first portions 122 a of the TECs120 and therefore the target material according to a desired temperatureprofile using directional flow of electricity through the TECs and incombination with the heat-transfer unit 140 to remove heat from the TECs120 when desired. By changing the direction of flow of electricity, thefirst portions 122 a of the TECs 120 may rapidly and precisely cool orheat and thereby rapidly and precisely cool or heat the target material101 according to a desired temperature profile over a desired period oftime.

When in cooling mode, the heat-transfer unit 140 removes heat generatedby the TECs 120 that would otherwise impact the ability of the TECs 120to cool the target material in a desired manner. For example, using afirst directional flow of electricity, the TECs 120 in combination withthe heat-transfer unit 140 may cool the target material 101 from aninitial ambient temperature Temp₁ (which may be the temperature oftissue of a patient, i.e. 35° C.-37° C.) to a lower temperature Temp₂(which may be 9° C. to −4° C. or −10° C. or −15° C. or −20° C.) over atime period Time₁ (which may be in the range of 0.1 to 5 seconds or 10seconds or 20 seconds). Using a second directional flow of electricityopposite to the first directional flow of electricity, the TECs 120 maythen heat the target material from Temp₂ (which may be 9° C. to −4° C.or −10° C. or −15° C. or −20° C.) to a higher temperature Temps (whichmay be room temperature or the normal temperature of tissue of apatient) over a time period Time₁ (which may be in the range of 0.1 to 5seconds). These ranges are examples and do not limit the scope andutility of the embodiments described herein. For example, additionaltemperature ranges are 15° C. to −10° C., 10° C. to −6° C., 10° C. to 0°C., 15° C. to −15° C., 10° C. to −10° C., or the like. For example, thetime range may be between 0.05 to 20 seconds, 0.05 to 10 seconds, or 0.1to 7 seconds and the like.

The directional flow of electricity may be altered from one direction tothe other to repeatedly cool or heat the target material, or vice versa,depending upon the desired application or use. Since the heating andcooling of the TECs 120 is driven by direction of current flow, thetemperature of the first portions 122 a of the TECs 120 and accordinglytemperature of the target material 101 thermally coupled to the TECs 120may be altered quickly, i.e. on the order of a fraction of a second to afew seconds, and with high precision, i.e. on the order of 0.1° C. to0.5° C., 1.0° C., 1.5° C. or 2.0° C. The low thermal inertia (e.g., lowheat capacity or low volumetric heat capacity) of the heat-transfer unit140 allows precise switching between cooling and heating modes in arange of 0.1 second to 5 seconds. The heat-transfer unit 140, thoughhaving a low profile of 0.7 mm-25 mm or 5 mm-15 mm, is capable ofremoving the high heat flux generated by the TECs 120 to cool the targetmaterial from its ambient temperature to a lower temperature, forexample between 9° C. to −4° C. or −10° C. or −15° C. or −20° C., withina time period of 0.1 second to 5 seconds, such as 2-3 seconds. In someembodiments, the heat transfer unit 140 generally has a thickness T of0.7 mm-1.0 mm.

The TECs 120 may be used together or operated independently to heat orcool the target material with a given surface area or volume. With eachTEC 120 generating heat within a given surface area, the heat-transferunit 140 is capable of removing the heat generated from the group ofTECs 120. Each TEC 120 may have its own heat-transfer unit 140 or asingle unitary heat-transfer unit 140 as shown in FIGS. 1A-1C may removeheat from all or a subset of the TECs 120. For example, theheat-transfer unit 140 may have a surface area greater than the combinedsurface area of the plurality of TECs 120. According to one aspect, theheat-transfer unit 140 and the TECs 120 may be arranged relative to oneanother and the target material 101 such that the surface of the targetmaterial (e.g., epidermis) may be cooled while allowing light orradiation energy or a mechanical treatment device to operate through orbetween the heat-transfer unit and TECs to heat deeper tissue to adesired treatment temperature that would otherwise be painful ordamaging to the epidermis.

The TECs 120 can be attached to a flexible contact member 110, orsubsets of one or more TECs can be attached to a rigid contact member110 and the rigid contact members 110 are coupled together by hinges toflex between rigid contact members 110. In such embodiments, each TEC120 or subset of TECs 120 can have an individual heat transfer unit 140with one or more phase-transition chambers 150, and the individual heattransfer units 140 can be thermally and physically separated(disconnected) from each other to allow the thermal management system toflex between individual TECs 120 or subsets of TECs 120. Thisconfiguration is particularly useful in applications where the targetmaterial 101 is non-planar, such as many body parts (e.g., shoulders,knees, ankles, face, torso, buttocks, head, etc.).

The TECs 120 may be arranged in an array of rows and columns or in anydesired pattern to achieve a desired objective. For example, a device asdescribed herein may include from 2 to 200 TECs 120 arranged within thesurface area of a thermally conductive contact member (e.g., a plate orfilm or support). Depending upon the number of TECs 120, the TECs 120may be arranged in a square pattern, rectangular pattern, circularpattern or other pattern relative to a thermally conductive contactmember depending upon the surface area of the target material 101 and/orthe contour of the target material 101. According to one aspect, theTECs 120 may be positioned horizontally with respect to one another inthe same plane. According to one aspect, TECs 120 may be positionedvertically with respect to one another such as by stacking TECs 120 oneon top of another.

Each TEC 120 may be operated independently to achieve different heatingor cooling of different locations of the target material 101, or all ofthe TECs 120 may be operated simultaneously to achieve uniform heatingor cooling of the target material 101. Subsets of the TECs 120 may beoperated independently to achieve different heating or cooling ofdifferent locations on the target material 101. Additionally, each TEC120 or subsets of the TECs 120 can have separate heat transfer units140, and the pairs of TECs 120 and heat transfer units 140 can beoperated independently or collectively.

Devices for regulating the temperature of a target material surface asdescribed herein including a heat-transfer unit 140 and the TECs 120 mayalso include one or more temperature sensors, heat flux sensors, and/orpressure sensors (identified collectively by reference number 170)operatively connected to the device to sense or detect temperature, heatflux or pressure at one or more locations along or within the device.Such temperature and pressure sensors provide feedback on the operationof the device for regulating the temperature of a target materialsurface and may assist in regulating the operation of the device toprovide a desired temperature or temperature profile of the targetmaterial. Accordingly, the devices for regulating the temperature of atarget material surface as described herein non invasively cool a targetmaterial, such as tissue, to a predetermined temperature. It is to beunderstood that the target material has a thickness and the cooling orheating of the target material using the device described herein maycreate a temperature profile as a function of depth of the targetmaterial. For example, the outer surface of the target material may havea temperature lower than the temperature of a treatment site within thetarget material. This results in a temperature profile of the targetmaterial. Once a desired temperature of the outer surface of the targetmaterial has been achieved or a desired temperature profile within thetarget material as a function of depth of the target material has beenreached, the target material may then be subjected to processing ortreatment at the predetermined temperature or temperature profile. Insome embodiments, a temperature profile is generated as a function oftime, location on the target material, and/or depth within the targetmaterial.

The contact member 110 can be one or more thermally conducting plates orsurfaces or films that thermally interconnect the heat-transfer unit 140to the TECs 120 and/or the TECs 120 to the target material 101. Forpurposes of further discussion, reference will be made to a thermallyconductive contact member, which can be a thermally conductive plate,surface, braid, fabric or film. The heat-transfer unit 140 may have itsown thermally conductive contact member, and the TECs 120 may have theirown thermally conductive contact member. The thermally conductivecontact member of the heat-transfer unit 140 may be affixed or otherwiseattached to the TECs 120. A single thermally conductive contact membermay be between the heat-transfer unit 140 and the TECs 120. A thermallyconductive contact member may be positioned at the bottom of the TECs120 or may be part of the bottom of the TECs 120 to provide a thermallyconnection between the TECs 120 and the target material 101. Thermallyconductive contact members may have a thickness between 0.01 mm and 5mm.

The thermally conductive contact members may have any suitableconfiguration, shape, design, thickness, etc., to contact a givensurface. The thermally conductive contact members may be rigid orflexible. The thermally conductive contact members may be flat, curved,convex, concave, bowed, undulating, pitted, ridged, dimpled, rough,smooth or have any other surface geometry sufficient for a particularthermal management method. Thermally conductive contact members may betransparent or nontransparent. A thermally conductive contact member mayinclude at least one or more thermally conductive materials known tothose of skill in the art such as thermally-conducting silicon, diamond,copper, silicon carbide, graphite, silver, gold, platinum, copper,sapphire, graphene, or silicon oxide--as well as other materials asdesired, needed or required.

According to one aspect in which the target material is human tissue, amethod cools and/or heats target tissue to predetermined temperatures inpredetermined times to rapidly and precisely cool and heat the targettissue. FIGS. 2 and 3 are graphs of temperature over time for variousembodiments of the thermal management system 100 described above withreference to FIGS. 1A-1C. FIG. 2 shows the rapid temperature response ofa method in which the contact member 110 was placed against a gelatinmass selected to simulate the temperature response in human tissue. Inthis method, at the starting points the TECs 120 (FIG. 1B) are driven sothat the first portions 122 a are cold and the second portions 122 b arewarm, and the two-phase heat transfer unit 140 is operated to removeheat from the second portions 122 b of the TECs 120. The TECs 120 arethen reversed so that the first portions 122 a are warmed and the secondportions 122 b are cooled, causing a rapid spike in the temperature from0° C. to over 20° C. in a few seconds. The TECs 120 can then be reversedagain so that the first portions 122 a again cool the contact member110, causing the temperature to rapidly decrease to the starting level.In addition to the rapid increase and decrease in temperature, this testalso shows that specific target temperatures can be achieved preciselywithout overshoot or undershoot and controllably maintained.

FIG. 3 shows another temperature/time plot of the temperature at variousdepths of 2 mm, 5 mm and 10 mm in a target material simulating humantissue. As shown, embodiments of the thermal management system 100described above with reference to FIGS. 1A-1C were able to withdrawenough heat to reduce the temperature from about 25° C. to 0° C. in 9minutes at a depth of 2 mm, 15 minutes at a depth of 5 mm, and 20minutes at a depth of 10 mm. This is a surprising result for thermalmanagement units having the small, low-profile size of the type shown inFIGS. 1A-1C. This is particularly useful for medical and aesthetictreatments because small, lighter applicators can be used, which enablesmore complex areas of the body to be cooled and provides more comfort tothe patient.

FIG. 4 shows another temperature and time plot of simulated tissue beingcooled and heated using a heat management system in accordance with thepresent technology. The target material 101 is initially at a normalphysiological temperature TT₁ (Tissue Temperature) of about 35° C. Asshown in FIG. 4, the tissue to be treated is at different temperaturesas a function of tissue depth with FIG. 4 showing the initialtemperature at the skin contact point, 0.1 mm, 0.5 mm and 1 mm depths.The temperature at the midpoint of the TECs between the first and secondportions 122 a-b is also shown by line TE. Also shown is the temperatureof about 8° C. and below where cooling provides an anesthetic effect andthe temperature of about −2° C. where tissue freezes superficially. Thethermal cooling and heating device is at an initial temperature DT₁ ofroom or ambient temperature of about 20° C. According to one optionalaspect, the device may be warmed to a pre-contact temperature DT₂ ofabout 35° C. to lessen uncomfortable contact of a relatively cold deviceto a relatively warm patient. The device at temperature DT₁ is thenbrought into contact with the skin surface and the TECs are activated tocool the target material from 20° C. to about −2° C. or 20° C. to about−10° C. in about 2 seconds and to provide cooling to the skin. Afterabout 5 seconds, the electricity flows through the device in a directionto cool the device and thereby cool the temperature of the skin contactpoint (skin contact green line) to about −2° C. in about 3 seconds. Thetissue at a depth 0.1 mm is cooled to a temperature of about 2° C. inabout 8 seconds. The temperatures of the tissue at depths of 0.5 mm and1.0 mm are higher and are above the temperature where the cooling canprovide an anesthetic effect. At this point, the skin can be treatedwith laser light, for example, where the skin at the contact surface andat a depth 0.1 mm benefit from an anesthetic effect from cooling. Atthis point, the direction of current is reversed such that the deviceheats the skin in about 2 seconds to a temperature of about 30° C. atthe skin contact point and about 27° C. at a depth 0.1 mm below thesurface. At this point, the direction of current is again reversed tocool the skin to a temperature of about −2° C. in about 3 seconds, wherethe skin can be treated with laser light, for example.

Several aspects of the present technology, such as the rapid change intemperature and precise control of the temperature of the targetmaterial 101, are enabled by the small size yet high heat transfer rateof the heat transfer unit 140 compared to the TECs 120 and/or thecontact member 110. In several embodiments, TECs 120 and the contactmember 110 or just the TECs 120 alone have a first volumetric heatcapacity and the heat transfer unit 140 has a second volumetric heatcapacity that is not more than one of 50%, 100%, 150%, 200%, 250%, 300%,400%, or 500% of the first volumetric heat capacity. More particularly,the first volumetric heat capacity of the heat transfer unit 140 is onlyabout 50%-200% or 100%-150% of the second volumetric heat capacity ofthe TECs 120 alone or the combination of the TECs 120 and the contactmember 110.

This cycle can be repeated any number of times to treat target tissueand at different target tissue locations. For example, the device can beused to cool down a first target tissue location TL₁ in about 2 secondsto a temperature of about 8° C. at which an anesthetic effect isachieved at the surface or 0.1 mm below the surface, and in about 3seconds to a temperature of about −2° C. where superficial freezingtakes place. The tissue TL₁ can be treated with laser light, forexample, and then the tissue TL₁ can be heated to a temperature of about30° C. or 20° C. or 15° C. in about 2 seconds. The device can then bemoved to a second tissue location TL₂ where the tissue can be cooled toan anesthetic treatment temperature in about 2-3 seconds for treatmentwith laser light. The second tissue location can then be heated to about30° C. in about 2 seconds and the device moved to a third tissuelocation TL₃ where the cooling, treatment and heating cycle is carriedout. This cycle can be repeated for any number of tissue locationsTL_(N). Additional cooling and/or heating profiles can be executed usingthe thermal management systems described herein. For example, thecooling or heating profile may be pulses of cooling (temperaturelowering) or heating (temperature raising) effect or sinusoidal pulses.The cooling and/or heating may be accomplished by desired electricalpulses or current through the thermoelectric unit which may be reversedas described herein. According to one embodiment, the cooling and/orheating may be accomplished by controlling the fluid pressure or flowrate to the heat-transfer unit, where such fluid pressure or flow rateis used to remove heat from a heat source contacting the heat-transferunit.

FIG. 5 is a graph showing the heat flux across the TECs 120 at pointswhere current is reversed at 8 seconds, at 10 seconds and at 13 seconds.As shown in FIG. 5, a high heat flux changes in a fraction of a second,which reflects the rapid cooling and heating of the TECs 120 and therapid cooling and heating of the target material 101. According to oneaspect, a target material to be cooled and/or heated is a tissue of apatient undergoing a treatment, such as an energy-based treatment suchas laser treatment such as for hair removal or dermatology treatment orneedle injection. Other treatments within the scope of the presenttechnology include radiotherapy for cancer treatment, thermal therapies(such as hypothermia or hyperthermia), combined thermal therapy andimmunotherapy, acne treatment (long pulse), body sculpting by coolingsubcutaneous adipose tissue, invasive or non-invasive RF treatments,HIFU, Ultrasound, laser tattoo removal, ablative laser skinrejuvenation, cellulite treatment, depigmentation and skin rejuvenation.According to such treatments, the tissue is cooled to numb the tissuebefore, during or after such treatment to reduce pain during treatment.According to one aspect, the tissue is cooled to numb the tissue before,during or after laser or needle treatment to reduce pain duringtreatment. Accordingly, the thermal cooling or heating devices providean anesthetic effect. After cooling, the tissue may be heated to bringthe tissue to a higher temperature, such as normal tissue temperature.Since the device is intended to contact tissue, the device may be heatedto normal tissue temperature to provide a pleasant contact to thepatient and to avoid an unpleasant contact such as when a cold device isplaced against the warm tissue of the patient.

According to one aspect, the device for cooling tissue as describedherein is integrated into a laser system or other medical device toprotect the epidermis and reduce pain in the treatment area and/orinhibit damage to non-target tissue (e.g., skin adjacent the targettissue). The device also provides temporary topical anesthetic relieffor laser treatments and injections, and thereby improves the efficacyof the laser or other medical device. With respect to timing ofirradiation of the laser or operation of the medical device, cooling cantake place before, during or after treatment, which includespre-cooling, parallel cooling and post-cooling.

The primary objective of laser therapy for patients with specificdermatoses is to maximize thermal damage to the target chromophoreswhile minimizing injury to the normal skin. However, in some cases, thethreshold dose of incident laser beam for epidermal injury can be veryclose to the threshold for removal of the chromophore. Dark-skinnedpatients are more susceptible to these problems because of highepidermal melanin which competes as a significant chromophore for laserenergy, leading to increased pain, blistering, scarring anddyspigmentation. The devices for heating and cooling tissue describedherein may selectively cool the most superficial layers of the skin toreduce pain, blistering, scarring and dyspigmentation. The goal iscooling of the epidermis to prevent the elevation of temperature beyondthe threshold temperature that causes thermal injury. Since coolingprotects the epidermis, a high fluence laser beam can be delivered tothe skin. This is referred to as the theory of spatial selectivity ofthe cooling. To target the chromophores within blood vessel, stem cells,hair follicles, etc., a treatment temperature should be reached.However, the treatment temperature will often damage the epidermalkeratinocytes and melanocytes. Device for cooling and heating skindescribed herein can maintain a lower temperature at the epidermal levelyet reach the required higher treatment temperature at the target depthin the tissue, which often provides better outcomes of laser procedures.In addition, cooling will diminish the amount of edema, which oftendevelops as a complication of laser procedures. Accordingly, the thermalmanagement systems of the present technology can protect the superficiallayers of the skin from collateral thermal damage.

Several embodiments of heat management systems in accordance with thepresent technology are a unitary component on the face of a hand-heldmedical instrument, or the heat management systems may be a separatecomponent that can be attached to the medical instrument. For example,the thermal management systems can be added to lasers including ahand-held laser emitting device, such as the Candela GentleLASE Pluslaser which is a non-invasive light therapy device specifically designedto eliminate unwanted hair from all parts of the body. The CandelaGentleLASE Plus generates a pulse of intense, concentrated light whichis directed through a small handpiece to the treatment site. Accordingto one aspect, the heat management systems may be fabricated at the tipof the handpiece of such commercially available laser systems. After theskin is cooled using a heat management system to protect the skin andprovide an anesthetic effect, the laser energy passes through the heatmanagement system and through the skin to the hair follicle, where theenergy is absorbed by pigment in the hair and hair follicle. As aresult, the hair root is selectively damaged without damaging thedelicate pores and structures of the skin. The laser is pulsed, or“turned on”, for only a fraction of a second. The duration of the pulsesis carefully calibrated so that laser energy will be absorbed by thehair follicle without transferring excessive heat to the surroundingskin. Thereafter, the heat management system warms up the skin and isthen moved to a second target skin location where the process isrepeated.

According to one aspect, the heat management systems cool the tissueupon contact and may be referred to as a contact cooling treatment.According to one aspect, the heat management systems may havetransparent parts or materials to allow light to pass therethrough whilethe heat management systems contact the tissue, such as when cooling orheating the tissue. According to another aspect, the heat managementsystems may have channels or holes therethrough to allow light oranother treatment modality or implement to pass therethrough while theheat management systems contact the tissue.

In accordance with certain aspects of the present technology, the heatmanagement systems cool the tissue while also controllably compressingthe skin/tissue to reduce blood flow in the target material; therefore,decreasing the oxyhemoglobin which is an active chromophore.Furthermore, skin compression brings deeper targets like the hairfollicles closer to the skin surface, which enhances the absorption oflaser energy so less fluence can be used to heat targets and/or moreenergy reaches the target.

The thermal management systems of the present technology are accordinglyuseful in treatment methods related to dermatological treatments ingeneral, including hair removal, tattoo removal, acne treatment,ablative laser treatment, invasive and non-invasive RF treatment,radiotherapy such as radiation beam therapy for treating canceroustissue, such as a tumor. The thermal management systems can be activatedbefore, during and after treatment. According to one aspect, the heatmanagement systems can be used to induce localized thermal damage totumor tissue, entirely within a desired surface area or at individuallocations or points within a given tissue surface area. For example,within a given tissue surface area, the tissue may have no or littlethermal damage and may also have locations of thermal damage. Thelocations of thermal damage may be ordered or may be random, as desiredaccording to a treatment.

FIG. 6 illustrates an embodiment of a thermal management system 600 forcooling a target material 101 in conjunction with a primary therapy. Thethermal management system 600 can be similar to the thermal managementsystem 100 described above, and like reference numbers refer to similaror identical components. The thermal management system 600 can include athermally conductive contact member 110 and TECs 120 such that severalTECs 120 are thermally coupled to the contact member 110. The TECs 120have electrical contact pads 610 at the first portions 122 a and contactpads 620 at the second portions 122 b, and electrical current can flowbetween the contact pads 620 and the contact pads 610 to cool the firstportions 122 a of the TECS 120, while heat flows in the oppositedirection as indicated by the arrows in the target and the arrows in theTECs 120.

The thermal management system 600 includes a two-phase heat transferunit 640 thermally coupled to the TECs 120. The heat transfer unit 640can be similar to the heat transfer unit 140 described above. Forexample, the heat transfer unit 640 can have a base 642, a top 644 and aphase-change chamber 646 defining a vapor space in the space between thebase 642 and the top 644. The heat transfer unit 640 can further includemicrofeatures 652, such as pins or elongated panels, that definemicrochannels 654. The microfeatures 652 can be superimposed withcorresponding TECs 120 as shown in FIG. 6. In operation, a working fluidin the microchannels 654 evaporates to cool the TECs 120.

The base 642 and the top 644 can be made from a transparent material orhave transparent portions, such as sapphire, diamond, glass, transparentceramics, alumina, transparent polymer nanocomposites with crystallizedalumina, etc. As a result, the thermal management system 600 is welladapted to be used with lasers and other skin treatment devices. Inoperation, the laser beam or other radiation beam can pass through thetransparent top 644 and base 642 in the areas between to TECs 120 toheat target tissue at a depth in the tissue, such as hair follicles orcollagen, while the TECs 120 and heat transfer unit 640 cool theepidermis and dermis where nerves are located. As a result, the lasertreatment can heat the target tissue to higher temperatures for longerperiods of time to enhance treatment outcomes, while the thermalmanagement system 600 cools the skin surface to protect the skin fromburning and to mitigate or even alleviate pain.

FIG. 7 is an isometric view of the thermal management system 600 of FIG.6 in operation. A volume of tissue 700 is shown in the X-Y-Z directionincluding fat and skin. The surface of the skin is at position 0 withthe depth of the tissue shown. A thermally conductive and transparentcontact member 110 contacts the skin and TECs 120 as described hereinare thermally coupled to the contact member 110. The two-phase heattransfer unit 640 as described herein is thermally coupled to the TECs120. In operation, a laser 660 or other treatment modality (e.g.,external beam radiation device) directs an energy beam 662 through thetransparent components in the spaces between the TECs 120.

FIG. 8A illustrates a side view of a thermal management system 800 andFIG. 8B is a top view of the thermal management system 800. The thermalmanagement system 800 includes a contact member 110, TECs 120 thermallycoupled to the contact member 110, and a two-phase heat transfer unit840 thermally coupled to the TECs 120. A liquid phase working fluidflows through a first conduit 850 to the heat transfer unit 840, and avapor phase of the working fluid flows from the heat transfer unit 840through a second conduit 862. The heat transfer unit 840 can be similarto the heat transfer unit 140, except that the heat transfer unit 840includes access holes 842 and the contact member 110 has openings 844aligned with the access holes 842. The access holes 842 and the openings844 are at least generally aligned with spaces between the TECs 120.

In operation, a needle or an energy beam 860, such as laser light,radiation beam or another type of beam, is directed through the accessholes 842 and openings 844. According to one aspect, the access holes842 and openings 844 also allow vapor and/or tissue debris to be ejectedfrom the target material surface during treatments, such as ablativelaser treatments. In this manner, the thermal management system 800 neednot be removed during treatment of the target material. The system 800can also include temperature sensors 870 at or near the TECs 120.According to one aspect, depending on the application, the two-phaseheat transfer unit 840, the TECs 120, and the high conductivity contactmember 101 are made from specific materials transparent to parts ofelectromagnetic wave spectrum.

According to one aspect, a vacuum system may be used to fix any of thethermal management systems 100, 600, 800 described above to the surfaceof the target material during treatment. The vacuum system is used tomaintain or improve thermal contact with the target material, such asskin. According to one aspect, the same vacuum system or a separatevacuum system may be used to evacuate or contain any tissue debris andvapors which may be created during ablative energy-based treatments suchas ablative carbon dioxide treatments. According to one aspect, fixingthe thermal management systems 100, 600, 800 to the skin surface duringtreatment prevents debris from the ablative laser treatment fromclogging access holes which may be present in the thermal managementsystem. The vacuum system also contains any vapor or debris therebypreventing the debris, particles and the gas to be inhaled by thepatient or the operator of the system. The vacuum system also helps toreduce the blood flow in the skin, which is useful for both laserprocedures and treatments for reducing subcutaneous adipose tissue forbody sculpting.

FIG. 9 is a schematic view of a thermal management system 900 havingTECs 120 and a heat transfer unit 940. The heat transfer unit 940 has anarray of microchannels 962 arranged such that discrete groups ofmicrochannels 962 are aligned with individual TECs 120. Themicrochannels 962 can be commonly connected at the inlets or the outletsby a common duct 964. The heat transfer unit 942 further includes anoptional access hole 942 and temperature sensors 970 located indifferent positions and layers throughout the system to provide feedbacksignals to control the heat flux and temperature at the device-targetinterface. Each thermal management system 900 can be an individual cell.

FIG. 10 is a schematic view of an assembly 1000 of several thermalmanagement systems 900. The assembly 1000 can include fluid deliverylines 1010 to carry the liquid phase of the working fluid to theindividual thermal management systems 900. The number and arrangement ofthe TECs as well as microchannels can be changed depending on anyspecific applications. A cap (not shown) covering the channels providesthe space required for vapor to exit the system. In some configurationsthe vapor is purged into the surrounding (e.g., open systems which canbe used with any embodiment herein), while in other configuration vaporis condensed back into the liquid phase in a closed system. Theinterface between the thermal management system 900 and the target canbe flat or curved with specific surface profiles for any particularapplication. The thermal management system 900 can be made out offlexible materials to conform to the shape of the target. The thermalmanagement system 900 can also include heating elements to quickly raisethe temperature at the target-system interface if needed. The system canoperate at pressures between 0.0001 bar and 20 bar and temperaturesbetween −270° C. and 1000° C.

FIG. 11 is a schematic view of another assembly 1100 of several thermalmanagement systems 900. In this embodiment, the individual thermalmanagement systems 900 do not have access holes, but instead have asolid central region 1110. The central region 1110 can be a transparentmaterial so laser light or other radiation beams can be transmittedthrough the center area to the target material below.

FIG. 12 is a schematic view of a semiconductor assembly 1200 having asemiconductor device 1201 and the thermal management unit 100 describedabove with respect to FIGS. 1A-1C. The thermal management system canalternatively have heat transfer units as described with respect toFIGS. 15A-2 E herein. The semiconductor device 1201 can be a processor,memory device, light emitting diode, or other heat producing device. Inthis embodiment, the contact member 101 is attached to the semiconductordevice 1201.

FIG. 13 is a schematic view of a semiconductor assembly 1300 having asemiconductor device 1301 and a version of the thermal management system100 without the contact member 110. The thermal management system canalternatively have heat transfer units as described with respect toFIGS. 15A-20E herein. In this embodiment, the semiconductor device has apassivation material 1302, and the TECs 120 of the thermal managementsystem 100 are attached to the passivation material 1302.

FIG. 14 is a schematic view of a number of devices 1401 a-n(collectively referred to as devices 1401), such as servers, that arecooled using thermal management systems in accordance with the presenttechnology. Each device 1401 can have a semiconductor assembly similarto or the same as the semiconductor assemblies 1200 and 1300 describedabove, or each device 1401 can have a separate thermal management system100, 600, 800 attached to the housing of the device 1401 in addition toor in lieu of the thermal management systems attached to thesemiconductor devices. Additionally, the thermal management systems canalternatively have heat transfer units as described with respect toFIGS. 15A-20E herein. Each of the assemblies 1200 and 1300 can becoupled to a common condenser 180. In operation, the assemblies 1200 and1300 can be cooled using the low-profile thermal management system 100internally to reduce or eliminate the need for large, cool airflows overthe devices 1401. This may save significant amounts of energy to coolmany servers compared to convention air-cooled servers. This mayaccordingly simplify constructions and maintenance of larger serverfarms as well.

Any of the foregoing heat-transfer units can include aspects of theevaporative structures described in U.S. Pat. No. 10,217,692 herebyincorporated by reference in its entirety and specifically for itsteaching of designs for two-phase evaporative cooling units. As Forexample, the evaporative structure may include a series of protrusionsextending down from a base into an evaporative fluid. Alternatively, theevaporative structure may include a series of walls forming a series ofchannels with evaporative fluid therebetween. The evaporative structuremay include a porous material configured to receive an evaporativefluid. The evaporative structure may include walls having a fractaltopography configured to receive an evaporative fluid. The evaporativestructure is designed to promote evaporation of the working fluid tocool the TECs. The evaporative structure is operatively connected to aninflow conduit or inlet port and an outflow conduit or outlet port tooperatively provide an evaporative fluid flow path through theevaporative structure. According to one embodiment, the inflow conduitis operatively connected to a pump and a reservoir of evaporative fluidto pump evaporative fluid through the evaporative structure. The inflowconduit is configured to receive the evaporative fluid as it enters theevaporative structure. The outflow conduit is configured to receive theevaporative fluid as it exits the evaporative structure. The evaporativestructure or a separate condenser may also include a condensing plate orunit to condense evaporated evaporative fluid for collection and/orredistribution to the evaporative unit, as is known in the art. Theevaporative structure may contact a plurality of TECs such that a singleevaporative structure cools a plurality of TECs.

Heat-transfer units according to the present technology mayalternatively include other two-phase cooling devices, such asJoule-Thompson cooling devices, spray cooling devices and the like. Suchheat-transfer units include cryogen spray (dynamic) cooling, such aspulsed cryogen spray using non-toxic 1,1,1,2-tetrafluoroethane alsoknown as R-134a (boiling point: −26.2° C.) or liquid nitrogen or liquidcarbon dioxide, for example. Other materials useful for cooling includeHFOs, HFCs, nitrogen oxide, alcohols, hydrocarbons (such as isobutane,propane), water, ammonia, particle-fluid mixtures, binary (or more thantwo) mixtures of materials (or fluids), and the like. A heat-transferunit may take the form of a container pressurized with a gas or fluidwhich when released or sprayed onto the surface of the hot side of thethermoelectric unit, causes cooling of the thermoelectric unit. When thecontents of the container or cartridge is empty, the container orcartridge may be disposed and a new full container or cartridge may beused with the system as a heat-transfer unit. A heat-transfer unitaccording to the present technology transfers the heat generated by theTECs where it is dissipated away from the TECs, thereby allowing theTECs to cool or otherwise regulate the temperature of the targetmaterial in the cooling mode of the system. The heat-transfer unitadvantageously prevents the TECs from overheating where heat generatedby the TECs overtakes the cooling ability of the TECs.

The two-phase heat transfer unit described in U.S. Pat. No. 10,217,692operates on the principle of evaporative cooling. An aspect of oneembodiment is a two-phase heat transfer device including a reservoirconfigured for containing a working fluid; a base member configured tobe in communication with and adjacent to a heat source; elongatedmembers extending distally away from the base member configured to formpassages between the elongated members, the elongated members include aproximal region and a distal region; and with the distal region of theelongated members at least partially inserted or immersed into theworking fluid.

According to one aspect, the two-phase heat transfer unit includes areservoir configured for containing a working fluid; a base memberhaving a first face and a second face, wherein the first face and thesecond face are generally opposite each other; the first face of thebase member is configured to be in thermal communication with andadjacent to a heat source, such as the TECs as described herein.Elongated members extend distally away from the second face of the basemember configured to form passages between the elongated members; theelongated members include a proximal region and a distal region, whereinthe distal region is configured to be at least partially inserted intothe working fluid; and the passages are configured to accommodate vaporthat may be produced from the working fluid so as to define a vaporspace. The elongated members may be a protrusion, a wall, a panel, apin, a post, or a rod; as well as any combination thereof. The basemember and the elongated members may be comprised ofthermally-conducting non-porous solid such as silicon, diamond, copper,silicon carbide, graphite, silver, gold, platinum, copper or siliconoxide—as well as other materials as desired, needed or required. Itshould be appreciated that the base member and the elongatedmembers—particularly the distal regions may be comprised of at least inpart porous material. The working fluid may comprise water, oils,metals, octane, hydrocarbons, Penatane, R-245ca, R-245fa, Iso-Pentane,halogenated hydrocarbons, halogenated alkanes, HFOs, HFCs, ketones,alcohols, or alkali metals—as well as other materials as desired, neededor required.

An aspect of an embodiment provides, but is not limited thereto, atwo-phase heat transfer device. The device may comprise: a reservoirconfigured for carrying a working fluid; a base member having a firstface and a second face, wherein the first face and the second face aregenerally away from each other, the first face of the base memberconfigured to receive thermal energy from a heat source; elongatedmembers extending distally away from the second face of the base memberand configured to define respective passages between adjacent elongatedmembers; the elongated members include a proximal region and a distalregion, wherein the distal region is configured to be at least partiallyinserted into the working fluid; and the passages are configured toaccommodate vapor produced from the working fluid so as to define avapor space.

According to one aspect, a two-phase heat transfer unit includes areservoir configured for carrying a working fluid; a base memberconfigured to receive thermal energy from a heat source; elongatedmembers extending distally away from the base member and configured todefine respective passages between adjacent elongated members; theelongated members include a proximal region and a distal region, whereinthe distal region is configured to be at least partially inserted intothe working fluid; and the passages are configured to accommodate vaporproduced from the working fluid so as to define a vapor space.

According to one aspect, a two-phase heat transfer unit includes areservoir configured for carrying a working fluid; a base memberconfigured to receive thermal energy from a heat source; elongatedmembers extending distally away from the base member and configured todefine respective passages between adjacent elongated members; and theelongated members include a proximal region and a distal region, whereinthe distal region is configured to be at least partially inserted intothe reservoir.

According to one aspect, a two-phase heat transfer unit includes areservoir configured for carrying a working fluid; a base memberconfigured to receive thermal energy from a heat source; elongatedmembers extending distally away from the base member and configured todefine respective passages between adjacent elongated members; and atleast some of the elongated members are configured to be at leastpartially inserted into the reservoir.

According to one aspect, a two-phase heat transfer unit includes areservoir configured for carrying a working fluid; a base memberconfigured to receive thermal energy from a heat source; elongatedmembers having at least one wall, wherein the elongated members extenddistally away from the base member and are configured to definerespective passages between adjacent elongated members; wherein theelongated members include a proximal region and a distal region, whereinthe distal region is configured to be at least partially inserted intothe working fluid; a recess topography disposed on the at least one wallof the elongated members, wherein the recess topography is configured toaccommodate the working fluid; and the passages are configured toaccommodate vapor produced from the working fluid so as to define avapor space.

The two-phase heat transfer devices for any of the embodiments describedwith reference to FIGS. 1A-20E provide high evaporation and coolingcapacity for use with the TECs when cooling the target material. Anadvantage associated with such two-phase heat transfer devices includesincreased cooling capacity per unit area, controlled and optimizedevaporation, prevention of boiling, and prevention of drying of theevaporator. An aspect associated with an approach may include, but isnot limited thereto, using a recess topology to increase suction ofworking fluid in the direction toward the heat source. An aspectassociated with an approach may include, but is not limited thereto,using a non-wetting coating or structure to keep working fluid away fromthe spaces between elongated members of an evaporator and using awetting coating or structure to form thin films of working fluid aroundthe distal region of the elongated members.

Two-phase heat transfer devices may utilize any combination of a wettingcoating, a wetting target material, a non-wetting coating, or anon-wetting target material to attract working fluid to certain areas ofthe device and repel working fluid from certain areas of the device. Forexample, the device may comprise a wetting coating such as a hydrophiliccoating or a lyophilic coating disposed on the distal region of theelongated members to attract working fluid. Alternatively, the distalregion of the elongated members may be comprised of a wetting targetmaterial (i.e., material) such as a hydrophilic target material orlyophilic target material. In another example, the device may comprise anon-wetting coating such as a hydrophobic coating or a lyophobic coatingdisposed on the proximal region of the elongated members and the secondface of the base member located between the elongated members to repelthe liquid working fluid. Alternatively, the proximal region of theelongated members and the second face of the base member located betweenthe elongated members may be comprised of a non-wetting target materialsuch as a hydrophobic target material (i.e., material) or a lyophobictarget material.

Two-phase heat transfer units may comprise a vapor space defined bypassages which widen in the direction of vapor flow. For example, thepassages may extend radially from a central region, wherein the pathwayis radial from the central region. In another example, widening vaporspace is formed by reducing the number of the elongated members (e.g.,per unit length/area) in the direction of vapor flow. Alternatively, thepassage may have a width that is uniform or narrows. Alternatively, thepassage may have a width that may provide a combination of widening andnarrowing, as well as remaining uniform.

FIGS. 15A-15E show a thermal management system 1500 having the contactmember 110, a TEC 120, and a two-phase heat transfer unit 1502 forcooling and/or heating a target material 1501 (also referred to hereinas “heat source 1501”), which can be any of the target materialsdisclosed above. Referring to FIG. 15A, the two-phase heat transfer unit1502 has a phase-transition chamber 1504 (also referred to herein as areservoir 1504) containing a working fluid 1505, a base 1506 contactingthe TEC 120, and microfeatures 1514 (also referred to herein aselongated members 1514) projecting from the base 1506 to form passages1520. FIG. 15B is an enlarged partial view of a single passage 1520(also referred to as a channel) of FIG. 15A, and FIG. 15C shows anenlarged partial view of the thin film region of a meniscus 1503 of theworking fluid 1505 shown in FIGS. 15A and 15B. The evaporating thin filmregion of the meniscus 1503 is where the bulk of evaporative heattransfer occurs as this region of the meniscus 1503 has a very lowthickness and therefore high conductive resistance. The non-evaporatingthin film region is where adhesion forces between liquid molecules andthe solid surface are extremely strong few if any of the molecules cantransition from the liquid phase to the vapor phase. Thus, theevaporating thin film region represents the region of enhancedevaporation and heat transfer.

The working fluid may be water, oils, metals, octane, hydrocarbons,Pentane, R-245ca, R-245fa, isopentane, halogenated hydrocarbons,halogenated alkanes, HFOs, HFCs, alkenes, ketones, alcohols, or alkalimetals. It should be appreciated that the working fluid 1505 should becompatible with the other materials that make up the device so they willnot react chemically to create non-condensable gases or cause otherdeleterious effects. Further, as an example, the working fluid may beany liquid or gas. Moreover, the working fluid may be molten metal orliquid metal, such as lithium or the like.

The elongated members 1514 can extend away from the base member 1506 inthe direction opposite the target material 1501 and the distal regionsof the elongated members 1514 are partially immersed or inserted in theworking fluid 1505. The heat travels through the solid mass of the basemember 1506 and down the microfeatures 1514 directly to the evaporatingthin film region of the meniscus 1503 where the bulk of evaporative heattransfer occurs. The heat is thus more readily provided to theevaporation thin film region, which in turn eliminates or at leastreduces the potential of boiling within a passage 1520 such that orderedand efficient evaporation can be maintained continually.

The two-phase cooling device can be designed to be operated in anyorientation given the orientation of the target material to be cooled orheated. For example, the two-phase cooling device may be designed to begravity insensitive (i.e., omnidirectional) if the channel width orspacing between the pins is smaller than a certain size such thatsurface forces (capillary forces) are dominant compared to volumetricforces such gravity. To avoid capillary forces from pulling the liquidinto the spacing between the pins or channels thereby reducing oreliminating the vapor space, a non-wetting coating can be used to repelthe liquid from entering that space. According to an additionalembodiment, a target material such as tissue may be below two-phasecooling device or it may be above the two-phase cooling device.

Still referring generally to FIG. 15A, another advantage of this (butnot limited thereto) and other embodiments of the two-phase heattransfer device is the efficient delivery of liquid phase working fluidto the evaporation sites. Because the liquid phase of the working fluid1505 is delivered to the reservoir of the phase-transition chamber 1504with only the tips of microfeatures 1514 disposed or immersed therein,the two-phase device does not need to overcome the high shear frictioninvolved with flowing the liquid phase of the working fluid through amultitude of narrow channels in conventional two-phase devices. Thus,dry-out problems are significantly reduced as there is less resistancein delivering the liquid working fluid 1505 to the phase-transitionchamber 1504 to replenish the evaporated mass.

As schematically reflected in the block diagram of FIG. 15D, the vaporregion 1522 (i.e., where the bulk of the evaporative heat transferoccurs) is adjacent to the heat source. Whereas the liquid phase of theworking fluid is relatively distant or remote from the heat source toavoid or mitigate boiling in the device and augment flow of liquidworking fluid, among other benefits.

FIG. 15E schematically illustrates the general circuit of the heat flow,HF, traveling within an embodiment of the two-phase heat transfer unit1540 of FIG. 15A. Heat from the heat source travels through the solidmass of the microfeatures 1514 (see FIGS. 15A-15C) and beyond the vaporspace 1522 (see FIGS. 15A and 15B) toward the region of the thin liquidfilm and intrinsic liquid meniscus. The liquid phase of the workingfluid 1505 in the reservoir is located furthest from the heat source andthereby requires the greatest distance for the heat to travel. As such,the thin liquid film and intrinsic liquid meniscus are relatively closeto the heat source. The alignment as schematically shown in FIG. 15E,enables the heat transfer device to generate superheated vapor withoutinducing boiling in the intrinsic liquid meniscus and liquid reservoir.Accordingly, this feature improves the quality of the heat removed bythe heat transfer device and the efficiency of the heat transfer device,which can be integrated in the various cooling applications as disclosedherein. Moreover, due to this arrangement, the temperature of theproximal portions of the solid mass of the microfeatures 1514 (see FIGS.15A-15C), i.e., “walls,” is higher than the saturation temperature ofthe thin liquid film and intrinsic liquid meniscus. This prevents liquidcondensate from accumulating in the vapor space 1522 (see FIGS. 15A and15B), which eliminates or reduces of blockage of the vapor space 1522with liquid condensate.

FIGS. 16A-16E schematically illustrate additional embodiments of thephase change thermal management system 1500 removing heat from thetarget material 1501. For example, the heat source 1501 can be thesurface of a computer chip as well as any of the other heat dissipationapplications disclosed herein. The target material 1501 is incommunication with a first face 1508 of a base member 1506, and a secondface 1510 of the base member is on the opposite side of the first face1508. The microfeatures 1514 extend distally away from the second face1510. For example, the base member 1506 and the microfeatures 1514 (orportions thereof) may comprise a thermally-conductive, non-porous solidsuch as, but not limited thereto, silicon, diamond, copper, siliconcarbide, graphite, silver, gold, copper, titanium, platinum, graphene,or metal alloys. Additionally, or in combination, the base member 1506and the microfeatures 1514 (or portions thereof) may have coating suchas, but not limited thereto, gold, platinum, copper, graphene, orsilicon oxide.

The microfeatures 1514 can be pins, posts, rods, walls, panels or otherstructures that efficiently conduct heat and can be constructed to havethe desired spacing between microfeatures 1514. Referring to FIG. 16A,the portion of the microfeature 1514 closer to the base member 1506defines a proximal region 1516 and the portion that is further away fromthe base member 1506 defines a distal region 1518. The distal region1518 is at least partially submerged in the working fluid 1505, creatinga thin film of the working fluid 1505 around the distal region 1518. Theheat flow 1513 travels (i.e., conduction) from the target material 1501through the base member 1506 and the proximal region 1516 to the distalregion 1518, and the heat is removed from the proximal region 1516and/or distal region 1518 when a controlled evaporation of the workingfluid occurs in the thin film area around the distal region 1518. Theevaporated liquid produces a vapor that fills a passage 1520 between themicrofeatures 1514 and the base 1506. The heat is transferred from thedevice when the vapor travels in vapor paths 1521 through the passages1520 defined by the microfeatures 1514 toward a condenser (not shown).The passages 1520 may, for example, be channels such microchannels ornanochannels.

FIG. 16A shows an embodiment wherein the microfeatures 1514 aregenerally straight. In such an embodiment, the proximal region 1516 ofat least one microfeature 1514 has a cross section that is substantiallyequal to the distal region 1518. FIG. 16B is an enlarged partial view ofpassage 1520 shown in FIG. 16A, particularly the vapor space 1522 andthe dimensions of the passage 1520 such as a height, H_(E), which is theheight of the elongated member or passage, a height, H_(V), which is theheight of the vapor space, and width, W, which is the width of thepassage (i.e., between elongated members 1514). It should be appreciatedthat while the stipple pattern representing the vapor space 1522 is onlyillustrated in the far-right passage 1520, the vapor space 1522 isapplicable to any and all passages 1520 (such as but not limited theretochannels or microchannels).

FIG. 16C shows another embodiment in which the proximal regions 1516 ofthe microfeatures 1512 are wider than the distal regions 1518. Themicrofeatures 1514 may accordingly be formed in a variety of shapes andcontours. The passages 1520 may be channels, such as microchannels ornanochannels. FIG. 16D is an enlarged partial view of passage 1520 shownin FIG. 16C, showing the vapor space 1522 and the dimensions of thepassage 1520, such as a height, H_(E), which is the height of theelongated member or passage, a height, H_(V), which is the height of thevapor space, and width, W, which is the width of the passage (i.e.,between elongated members, for example). While the stipple patternrepresenting the vapor space 1522 is only illustrated in the far-rightpassage 1520, that the vapor space 1522 is applicable to any and allpassages 1520 (such as but not limited thereto channels ormicrochannels).

Without wishing to be bound by any limitations, the dimensions of thedevice and the dimensions and spacing of the microfeatures 1514 may beany of the foregoing dimensions described above with respect to FIGS.1A-1C. Additionally, various embodiments may have passages (e.g.,channels) with the following dimensions: the width, W, may range fromabout 100 nanometers to 100 s of microns; the length, L, may range fromabout 1 micron to 100 centimeters; and the height, H, may range fromabout 5 microns to 5 millimeters. In other examples, the width, W, couldrange from about 10 nanometers to 10 millimeters, the length, L, mayrange from 100 nanometers to 1,000 centimeters or more, and the height,H, may range 100 nanometers to 10 s of centimeters. Any of thesedimensions are applicable to any of the passages indifferent of thestructure of the elongated members (shape, angles, contours) that definethe passages. The dimensions may vary between respective passagesrelative to one another. Moreover, the dimensions may vary within agiven passage itself. Again, these dimensions are merely illustrative.

The vapor space 1522 is the space within the passage 1520 that is filledby vapor during operation. The vapor space 1522 can be defined as thespace between the surfaces of the microfeatures 1514, the surface of thesecond face 1510 of the base member 1506, and the surface of the workingfluid 1505 (e.g., the meniscus 1503 of the working fluid 1505). Thevapor space 1522 can be created by repelling the working fluid 1505 fromthe passage 1520 via a non-wetting coating 1528 on the proximal region1516 of the elongated members and the second face 1510 of the basemember. Alternatively, the vapor space 1522 can be created by repellingthe working fluid 1505 from the passage 1520 by having the proximalregion 1516 of the elongated members and the second face 1510 of thebase member be comprised of a non-wetting material 1530 (i.e., materialof the structure itself or applicable component, for example). The vaporspace 1522 is typically smaller than the passage 1520 because theworking fluid fills the portion of the passage 1520. Coating the surfaceof the distal region 1518 with a wetting coating 1524 or having thedistal region 1518 be comprised of a wetting target material 1526attracts the working fluid 1505 to the distal region 1518, causing theworking fluid 1505 to fill the portion of the passage 1520 that isnearby.

In some embodiments, the wetting and/or non-wetting properties of thematerials ensure proper flow of the liquid phase of the working fluid toareas where it is desired. The wetting/non-wetting coatings and/ortarget material of the structure itself may include any portion of thedevice (base or elongated members) as desired, needed or required. Theportion may be of any size, area, thickness or contour as desired,needed or required. Additionally, in some embodiments the wetting and/ornon-wetting properties of the materials used in the heat transfer deviceensure proper flow of the vapor phase of the working fluid to areaswhere it is desired that the working fluid be in the vapor phase. Thewetting and non-wetting properties may be provided by coating materialsor by the inherent properties of the target material materials used toconstruct the relevant portions of the device. The working fluid 1505should be compatible with the base member 1506 and microfeature 1514 orany coating materials used so that they will not react chemically tocreate non-condensable gases or cause other deleterious effects.

According to one aspect, a wetting coating may be on at least a portionof the distal region 1518 of the microfeature 1514 and a non-wettingcoating is on a portion of the proximal region 1516 of the microfeature1514. Again, the location of the wetting/non-wetting coating (orstructure) may vary accordingly. It is to be understood that thetwo-phase cooling system may include wetting coatings, non-wettingcoatings or both wetting coatings and non-wetting coatings as desired.

Examples of materials suitable as wetting coating or wetting targetmaterial include, but are not limited to: hydrophilic materials,particularly when water is used as working fluid 1505; and lyophilicmaterials, particularly when a fluid other than water is used as workingfluid 1505. Examples of materials suitable as non-wetting coating ornon-wetting target material include, but are not limited to: hydrophobicmaterials, particularly when water is used as working fluid 1505; andlyophobic materials, particularly when a fluid other than water is usedas working fluid 1505. Examples of materials suitable for use ashydrophilic/wetting materials may include, but not limited thereto thefollowing: Metals, glass, ceramic, Silicon, Silicon Carbide, andDiamond, for particular group of working fluids. Examples of materialssuitable for use as hydrophobic/non-wetting include, but not limitedthereto: certain polymers, halogenated hydrocarbons, or chemicallyaltered surfaces of the metals. It should be noted that wettingcharacteristics are defined for a liquid-solid pair. In an approach, itshould be noted that the exact wetting characteristics of a particularembodiment may be determined by the specific interaction between achosen working fluid 1505 and chosen wetting coating and/or wettingtarget material surface (material) of the elongated member or basemember. Thus, for example, a working fluid 1505 and wetting coating canbe selected jointly according to the exact wetting properties of theliquid-solid pair.

The heat flow 1513 passes through the distal region 1518 of themicrofeature 1514 to the working fluid 1505. The wetting properties ofthe wetting coating cause the liquid portion of the working fluid 1505to wet the distal region 1518 of the microfeature 1514, creating ameniscus in the liquid phase of the working fluid 1505. As with otherembodiments of the present technology, an evaporating thin film regionwill be present in a portion of the working fluid 1505 in contact withthe distal region 1518 of the microfeature 1514. Depending on the statusof the coating (e.g., portion, location and type of coating), theworking fluid 1505 may be in contact with the proximal region 1516 ofthe microfeature 1514. High heat transfer is achieved by the ability ofthe continually active thin film evaporation site (as shown in FIG. 15Cand discussed with respect to FIGS. 16A-16D) to take full advantage ofthe latent heat of evaporation of the working fluid 1505. In addition,in this particular embodiment, the non-wetting coating prohibits theworking fluid 1505 from covering or filing (or invading) the spacesurrounded by the proximal region 1516 of the microfeature 1514. Thisallows the space to act as a vapor passage (e.g., channel or similarstructure) for the vapor produced as a result of the evaporation, andflow in its respective vapor pathways. Additionally, the non-wettingcoating allows the vapor to flow to the condenser with minimizedresistance.

Creating a vapor space in the passage reduces boiling and bubbling.Evaporation occurs at the distal region of the elongated member throughcontrolled and thin-film evaporation. Moreover, in some embodiments, forexample those embodiments that may utilize a horizontal configuration,the flow of liquid is less-restricted because it does not travel throughnarrow passages. The liquid at least in part flows in an open area inthe phase-transition chamber 1504, resulting in lower pressure drop.This pooling may be readily applicable wherein a horizontalconfiguration is implemented or wherein gravitational forces on thefluid in the passages and/or reservoir is essentially negligible. Inother orientations, for example, judicious placement of wicks or shapingof passages may be implemented to induce and aid the flow of the liquid.Without wishing to be bound by scientific theory, it is desirable toallow the liquid to flow in the pool (freely) and allow the vapor toflow in the space between channel walls or between pins or a poroustarget material, etc. Vapor has a much smaller viscosity compared toliquid. Arrangements described herein reduce the overall pressure droprequired to circulate/flow the fluid through the system both for open orclosed systems. According to one aspect, the active evaporating part ofthe meniscus may be closer to the heat source in certain configurations.According to one aspect, the thin-film part of the liquid meniscus isclosest to the heat source and is exposed to highest temperature. Thisaspect eliminates/lowers the chance of pool boiling in the channel sincethe bulk of the liquid can remain in below boiling-temperature(subcooled) while the intense evaporation occurs in the top part wherethe thin film is located.

FIG. 17A schematically illustrates an embodiment of an elongated member1514 of the device with wetting a wetting coating 1524 and a non-wettingcoating 1528. The wetting coating 1524 may be positioned on a portion ofthe distal region 1518 of the microfeature 1514. In this embodiment, anon-wetting coating 1528 is positioned upon a portion of the proximalregion 1516 of the microfeature 1514. Again, the location of thewetting/non-wetting coating (or structure) may vary accordingly.

Examples of materials suitable as wetting coating 1524 or wetting targetmaterial include, but are not limited to: hydrophilic materials,particularly when water is used as working fluid 1505; and lyophilicmaterials, particularly when a fluid other than water is used as workingfluid 1505. Examples of materials suitable as non-wetting coating 1528or non-wetting target material include, but are not limited to:hydrophobic materials, particularly when water is used as working fluid1505; and lyophobic materials, particularly when a fluid other thanwater is used as working fluid 1505. Examples of materials suitable foruse as hydrophilic/wetting materials may include, but not limitedthereto the following: Metals, glass, ceramic, Silicon, Silicon Carbide,and Diamond, for a group of working fluids. Examples of materialssuitable for use as hydrophobic/non-wetting include, but not limitedthereto: certain polymers, halogenated hydrocarbons, or chemicallyaltered surfaces of the metals. In one approach, the wettingcharacteristics of an embodiment may be determined by the specificinteraction between a chosen working fluid 1505 and chosen wettingcoating 1524 and/or wetting target material surface (material) of theelongated member or base member. Thus, for example, a working fluid 1505and wetting coating 1524 can be selected jointly according to the exactwetting properties of the liquid-solid pair.

The heat flow 1513 conducts to the distal region 1518 of themicrofeature 1514 and from the distal region 1518 to the working fluid1505. The wetting properties of the wetting coating 1524 cause theliquid portion of the working fluid 1505 to wet the distal region 1518of the microfeature 1514, creating a meniscus 1503 in the liquid phaseof the working fluid 1505. As with other embodiments of the presenttechnology, an evaporating thin film region will be present in a portionof the working fluid 1505 in contact with the distal region 1518 of themicrofeature 1514. Depending on the status of the coating (e.g.,portion, location and type of coating), the working fluid 1505 may be incontact with the proximal region 1516 of the microfeature 1514. Highheat transfer is achieved by the ability of the continually active thinfilm evaporation site (as shown in FIG. 15C and discussed with respectto FIGS. 16A-16D) to take full advantage of the latent heat ofevaporation of the working fluid 1505.

In addition, in this embodiment, the non-wetting coating 1528 prohibitsthe working fluid 1505 from covering or filing (or invading) the spacesurrounded by the proximal region 1516 of the microfeature 1514. Thisallows the space to act as a vapor passage (e.g., channel or similarstructure) for the vapor produced as a result of the evaporation, andflow in its respective vapor pathways. Additionally, the non-wettingcoating 1528 allows the vapor to flow to the condenser with minimizedresistance.

FIG. 17B schematically illustrates an embodiment of an elongated memberof the device with a wick 1538 (or similar structure) to ensure that thedistal region 1518 of the microfeature 1514 remains in constant contactwith the liquid phase of the working fluid 1505. The wick 1538 may alsoincrease flow of the working fluid through the elongated members andpassages. In such an embodiment, the wick 1538 may provide capillarydraw in order to move the liquid portion of the working fluid 1505 fromthe condenser portion of the device to the evaporator portion. Otherapproaches may be used, such as systems similar to wicking or pumpingsystems. Such pumping approaches may include electro-osmotic pumpingthat may be used to promote the flow toward the thin film.

The wick 1538 may ensure the continuity of the contact between thedistal region 1518 of the microfeature 1514 and the liquid portion ofthe working fluid 1505 along the entire length of the microfeature 1514.In this way, the capillary draw of the liquid portion of the workingfluid 1505 to the evaporation sites along the microfeatures 1514 is notcompromised and problems associated with dry-out are reduced or avoided.

In other embodiments, the liquid portion of the working fluid 1505 maybe moved from the condenser to the evaporator by relying on gravity andallowing the working fluid 1505 to pool back to the reservoir in theevaporator. Continuous contact between the distal region 1518 of themicrofeature 1514 and the liquid portion of the working fluid 1505 maythen be achieved through a combination of wetting and/or non-wettingtreatment of the relevant portions of the microfeature 1514.

Referring now to FIG. 18A, in some embodiments the microfeatures 1514may be constructed to form vapor passages 1520 that generally widenalong the pathways 1521 in which the accumulating vapor flows. Thus, thepassages 1520 configured by the microfeatures 1514 can accommodate vaporflow in a multitude of vapor pathways 1521. In this embodiment, thepassages 1520 generally widen to accommodate increasing amounts of vaportraveling in their various vapor pathways 1521. Near the center of adevice, the vapor flow rate will be less than near the edge where allthe accumulated vapor flow passes before exiting the evaporator towardsa condenser. Numerous aspects of the elongated members may be configuredand varied, such as, but not limited thereto: size, shape, area,contour, location or position, number provided, and density of thepopulation provided. In a related manner, the various vapor pathways maybe configured to be regular or irregular, as determined by theparticular configuration of elongated members chosen.

The passages 1520 may be, for example, a channel such as a microchannel.Although, not expressly illustrated, the passage 1520 may have adesignated width, W, and area, A, as desired, needed or required. Any ofthe aforementioned dimensions may increase above or below the micro sizemagnitude. Additionally, any of the passages may include a variety ofshapes and contours as required, needed or desired. They may have avariety of angles or pitches. The passages 1520 may be, for example butnot limited thereto, a channel such as a nano-channel.

In FIG. 18A, this general widening of the passages 1521 is achieved byarranging the microfeatures 1514 to define radial passages 1520 toaccommodate the pathways 1521 of vapor. In an embodiment such as this,the closely configured microfeatures 1514 near the center achieve thebenefit of efficient heat transfer, and the close configuration does nothinder the flow of vapor because the amount of vapor accumulating in theportion of the passages 1520 near the center is relatively small. As themicrofeatures 1514 extend away from each other in the direction of thepathways 1521, the passages 1520 widen in order to accommodate theaccumulation of vapor along the length of the pathways 1521.

The embodiment shown in FIG. 18A is only one such example. The wideningof the passages 1520 along the pathways 1521 of vapor flow can beaccomplished through a variety of embodiments. For example, the passages1520 can be irregularly shaped, and the microfeatures 1514 that definethe passages 1520 can be constructed to have intermittent, as opposed tocontinuous, positioning along the passages 1520 accommodating thepathways 1521 upon which the vapor will travel.

Referring now to FIG. 18B, other embodiments of the present technologymay be constructed such that the microfeatures 1514 form passages 1520that are substantially parallel. In this type of arrangement, thepassages 1520 do not widen in the direction in which accumulating vaportravels but instead they maintain a substantially constantcross-sectional area along the length of the passages 1520.

FIG. 18C shows another embodiment of the present technology in which themicrofeatures 1514 are positioned in a radial fashion from a centralpoint 1542. In an embodiment such as this, the microfeatures 1514 thatdefine the passages 1520 are constructed to have intermittent, asopposed to continuous, positioning along passages 1520 to accommodatethe pathways 1521 of vapor flow. This may be accomplished, for example,by utilizing microfeatures 1514 fashioned in the form of pins, posts,rods, (or similar structure) or combinations of these. This may also beaccomplished, for example, by utilizing microfeatures 1514 fashioned inthe form of panels or walls of intermittent length, as opposed to panelsor walls that run the length of the evaporator portion of the device.

In the embodiment represented in FIG. 18C, the microfeatures 1514 areplaced in an intermittent, radial fashion such that the number ofavailable passages 1520 generally increases along the pathways 1521 uponwhich the accumulating vapor travels. In this manner, the overall vaporspace defined by the passages 1520 may generally widen and increasealong the radiating pathways 1521 upon which the accumulating vaportravels. Although as illustrated, the width of the passages remainsabout the same. However, as the pathway extends radially outward thepopulation density of the elongated members (e.g., rods or pins) maydecrease so that the width of the passages may increase.

FIG. 18 D shows yet another embodiment that uses a radial positioning ofmicrofeatures 1514 from a central point 1542. As with other embodiments,the embodiment represented by FIG. 18D forms passages 1520 thatgenerally increase in size and/or number along the passages 1520 toaccommodate pathways 1521 of vapor flow, thus increasing the overallvapor space capable of accommodating the accumulating vapor. Forinstance, the elongated members in the form of pins, post or rods (orsimilar structure), may be more densely populated toward the center ofthe device compared to the outer or circumferential portion of thedevice.

Referring now to FIG. 18E, some embodiments may use sections ofmicrofeatures 1514 that are substantially parallel to each other inorder to define passages 1520 that are also substantially parallel toeach other. In this embodiment, the number of microfeatures 1514 withinany passage 1520 generally decreases in the direction of the pathway1521 upon which the accumulating vapor travels. This may beaccomplished, for example, by positioning a number of microfeatures 1514near the center and extending them to different lengths such that somedo not extend all the way to the edge of the device, thus allowing thepassages 1520 to widen and accommodate the accumulation of vapor in avariety and multitude of pathways 1521. In this manner, the overallvapor space defined by the passages generally widens and increases inthe direction of the passages 1520 and pathways 1521 of vapor flow.

Referring now to FIGS. 19A-19D, some embodiments may use one or moremicrofeatures 1514 that are fashioned in the form of walls or panels. Insome embodiments, the walls or panels may be curved or contoured. Someshapes may include multiple contours (FIG. 19A); multiple angles (FIG.19B); single curve (FIG. 19C); and straight alignment (FIG. 19D). Itshould be appreciated that the different embodiments of microfeatures1514 represented herein may be used in combination with each other or incombination with other forms. Additionally, the form of microfeatures1514 used in any embodiment may be uniform or substantially uniform. Anexample of a curve design may be reflected by a spiral pattern.

FIGS. 20A-20E show additional forms of microfeatures 1514. Theseembodiments may be used to form one or more elongated members in theform of rods, pins, or posts (or similar). The microfeatures 1514 mayhave the following one or more different cross-sections; circular, oval,rectangular (or square), hexagonal, and triangular, as well as anycombination thereof. Said differently, the cross section may be of anypolygonal cross section or any conceivable geometrical shape. Forexample, the elongated members may be at least one of: triangular,triangular prism, a pyramid, a cone, and a cylinder.

According to one aspect, the heat flux generated by the semiconductordevice of the present technology is dissipated by the heat-transferunit. This heat flux can be approximated as follows. Assuming the targetto be cooled is a cube of tissue with dimensions of 1 cm wide by 1 cmlong by 1 mm thick, the contact cooling system is to reduce thetemperature of the mass enclosed in this volume from 35° C. to 5° C.,with the assumption that biological tissue is approximated as liquidwater. The thermal energy which must be extracted from the target tolower its temperature from its initial temperature T₁ to targettemperature T₂ is:

E=ρVC _(p)(T ₁ −T ₂)

Where ρ is the material density, V is the volume, and C_(p) is thespecific heat capacity.

For the case described above, the variables are as follows:

$\rho = {1000\frac{kg}{m^{3}}}$ V = 10⁻²m × 10⁻²m × 10⁻³m = 10⁻⁷m³$C_{p} = {4180\frac{J}{{kg} \cdot C}}$ T₁ = 35  C T₂ = 5  C

Therefore the total thermal energy E will be:

E=12.5 J

The thermal energy will be extracted across the top face of the targetwhich has a surface area A of:

A=10⁻² m×10⁻² m=10⁻⁴ m ²

For some applications including pain management in dermatologyenergy-based treatments, it is desired that the target temperature isreduced from 35° C. to 5° C. in a few seconds (for example 2-3 seconds).

The heat flow Q_(c) and the heat flux q_(c), can be calculated as

$Q_{c} = {\frac{E}{t} = {\frac{12.5\mspace{14mu} J}{2\mspace{14mu} s} = {6.25\mspace{14mu} W}}}$$q_{c} = {\frac{Q}{A} = {\frac{6.25\mspace{14mu} W}{10^{- 4}m^{2}} = {62.5\mspace{14mu}{kW}\text{/}m^{2}}}}$

In the thermal management system described herein, q_(c), is the averageheat flux into the cold side of the thermoelectric (Peltier) module. Theheat flux out of the hot side of the thermoelectric module is determinedby characteristics of the thermoelectric module and the temperatures atthe hot and cold sides of the thermoelectric module. For an exemplarythermoelectric module (potted version from TE Tech module TE-65-0.6-0.8)and for the hot and cold side temperatures at −10° C. and −20° C.,respectively, the heat flow on the cold and hot side of the module are:

Q_(C,TE)=8 W

Q_(H,TE)=25 W

Since Q_(C,TE)>Q_(C) the thermoelectric module is capable of removingthe thermal energy from the target quickly enough to meet therequirement of cooling the target from 35° C. to 5° C. in 2 seconds.

The heat flux on the hot side of the Peltier module, q_(H,TE) is:

$q_{H,{TE}} = {\frac{Q_{H,{TE}}}{A_{module}} = {\frac{25W}{156\mspace{14mu}{mm}^{2}} = {160\frac{kW}{m^{2}}}}}$

The two-phase cooling system mounted on the hot side of thethermoelectric Peltier module has to remove the heat at a rate specifiedabove in order for the hybrid system to cool the target at the specifieddesired rate (30° C. temperature drop in 2 seconds). The cooling systemis designed to provide cooling capacities as high as

$10\frac{MW}{m^{2}}$

at small temperature differences (less than 5° C.) between the heatsource (Peltier module) and the working fluid. The total thermal energywhich should be removed by the two-phase cooling system over the 2seconds of operation of the system in its cooling mode is:

E _(H) =Q _(H) ×t=25W×2s=50 J

The mass for the working fluid that has to turn from liquid into vaporto remove this amount of thermal energy, E_(H) is:

m _(Ref) =E _(H) /h _(fg)

in which h_(fg) is the latent heat of vaporization for the workingfluid. Using HFO-1234ze as working fluid:

h _(fg)=190 kJ/kg

Therefore, the required mass for the working fluid to complete thecooling cycle is:

m _(Ref)=2.63×10⁻⁴ kg

The mass flux of evaporation is:

${\overset{.}{m}}_{Ref} = {\frac{m_{Ref}}{A_{TE} \times t} = {\frac{2.63 \times 10^{- 4}{kg}}{156 \times 10^{- 6}m^{2} \times 2\mspace{14mu} s} = {0.8\frac{kg}{m^{2} \cdot s}}}}$

This is a large mass flux of evaporation. The contact surface areabetween liquid and solid to induce liquid evaporation at this rate canbe calculated using equations described in U.S. Pat. No. 10,217,692. Thelarge contact surface area between liquid and solid requires manychannels or high contact surface area between the solid channels and thefluid packaged in a 1 cm×1 cm area and imposes large pressure drop onthe liquid. The pressure gradient to induce such flow rate is verylarge. An exemplary channel design useful in the present technology is afractal topology that enables fluid flow through the phase-changecomponent of the system at very low-pressure gradients (or passive, i.e.self-driven, flow in some cases). The cooling system described abovewill have a compact footprint (less than 5 mm) and can be integratedinto a wide range of energy-based tissue treatment systems and otherapplications. The entire system, whether made with transparent ornontransparent materials, provides ultra-fast cooling and very highcontrollability in a very compact package.

Another aspect of the present technology is to monitor the temperaturedistribution in the target material at different depths or layers withinthe target material during energy-based treatments. For example, oneaspect is to non-invasively monitor the temperature distribution insidea volume of mammalian tissue (e.g., human tissue) usingelectromagnetic/mechanical waves during an energy-based therapy ortreatment (e.g., laser treatments, radiation beam treatments, orcryo-based treatments such as reducing subcutaneous adipose tissue viacooling, ablating lesions (e.g., freezing lesions), etc.). In operation,the molecules of the tissue absorb, scatter, or reemit the propagatingwave, and the effect of thermal energy on the molecules changes theinteraction of the waves with the tissue. These changes can be detectedby measuring changes in the return wave or other energy received by adetecting transducer. This can provide online/real-time temperaturemonitoring with high accuracy and reliability. The non-invasive natureof this aspect of the present technology provides a robust tool foraccurately monitoring different types of tissue that enhances the safetyand reliability of energy-based treatments and reduces the risk ofdamage to non-target treatment areas.

In some embodiments, a mechanical wave (e.g., ultrasound) can be appliedto the tissue through an array of transducer elements (e.g.,piezoelectric transducers). Referring to FIGS. 21A-21C, a non-invasivemonitoring system 2100 can include an array 2101 of transducers 2110configured to transmit ultrasonic energy to the target material 101 anddetect return components of the ultrasonic energy. The transducers 2110of the system 2100 are arranged in a single row (FIG. 21B) or in severalrows (FIG. 21C). FIGS. 22 and 23 show an alternative non-invasivemonitoring system 2200 having a transducer array 2201 with transducers2210 spaced apart by gaps G. These arrangements can be a singletransducer instead of an array, or in the case of an array with multipletransducers any number of transducers can be used (there is no limit onthe size or number of transducers).

The arrangement of the transducers 2110 and 2210 shown in FIGS. 22A-23are linear, but in other embodiments the transducer arrays 2101 and 2201can be curvilinear, 1.5D array, 2_D array, convex, concave, annular,internal focus, skewing, variable angle, dual linear, dual 1.5D, orcoaxial (annular). The scan of the treatment area can be along a linearpath or by sweeping the wave using phased-array transducers. Thefrequency of the transmitted waves depends on the depth and the desiredresolution.

Referring to FIGS. 21A-23, the array of transducers can produce a beamto monitor the thermal profile of the whole treatment area usingdifferent delayed phase waves. The elevation focus depth can change froma depth within the tissue of 0.5 mm to 20 cm depending on location ofthe region of interest.

The transducer arrays 2101 and 2201 can be located inside and/or outsideof the applicator of an energy-based device. For example, the cluster oftransducers in an array can be located at different areas in and/oroutside of the applicator to be in contact with the tissue.

FIG. 24 shows a non-invasive monitoring system having transducer array2401 having transducers 2410 a-b (referred to collectively as“transducers 2410”) arranged on a curved energy-device applicator 2420.The energy-device application 2420 can be the contact member of any ofthe thermal management systems described above with reference to FIGS.1A-20E, such as contact member 101. This is particularly useful incryo-based applications where the contact member directly cools theepidermis to treat subcutaneous tissue, such as reducing subcutaneousadipose tissue for body sculpting. The energy-device application 2410can alternatively be a component of a laser system or radiation beamsystem that heats the target material. The non-invasive monitoringsystem can have first transducers 2410 a inside the applicator 2420contacting the tissue and second transducers 2410 b outside of theapplicator 2420 that are also contacting the tissue. The thermaldistribution inside the tissue changes over time and can be monitoredconstantly or episodically. This can be done by turning the transducerson/off or activating them continuously throughout a procedure.

Other embodiments of non-invasive tissue monitoring use polarizedelectromagnetic (EM) waves with wavelengths up to 100000 μm. These wavesare either transmitted, reflected, absorbed, refracted, diffracted, orscattered as they travel through tissue. For example, during anenergy-based treatment, the applied energy changes the temperature ofthe tissue, which alters its behavior/response to an EM wave. Thevariation in the temperature of the tissue at various depths within thetissue can thus be monitored through measuring the changes in thepolarization, amplitude, wavelength, frequency, time of flight, phaseshift, and the intensity of the EM wave.

FIG. 25 shows a non-invasive monitoring system 2500 having at least oneEM source 2510 and at least one EM detector 2520. In the illustratedembodiment, the system 2500 has one EM source 2510 and three EMdetectors 2520 a-c (referred to collectively as “EM detectors 2520”),but any number of EM sources 2510 and EM detectors 2520 can be used. TheEM source(s) 2510 and EM detectors 2520 can be mounted to an applicator2550, such as the contact member of any of the foregoing thermalmanagement systems described above with reference to FIGS. 1A-20E or anylaser/radiation type tissue treatment device. The distance between thesource 2510 and the detectors 2520 is a function of the depth of thetarget treatment area in the tissue, such as 0.5 mm to severalcentimeters. The arrangement of the source(s) 2510 and detectors 2520depends on the thermal profile progression of the cooling/heatingtreatment through the tissue. In operation, one or more EM waves aretransmitted to the target material 101 (e.g., mammalian tissue) via thesource 2510 and the backscattered energy is recorded by the detectors2520. In this embodiment, the EM travels through a banana-shape pathwayto the detectors 2520.

FIG. 26 illustrates another embodiment in which several sources 2510 andseveral detectors 2520 are at different locations and distances fromeach other. The sources 2510 and detectors 2520 can produce/detect EMwaves 2610 that are received directly from a source 2510 to a detector2510 or EM waves 2602 can be curved (e.g., banana-shaped) or otherwisenot directly linear. The arrows 2603 and 2604 indicate the polarizationaxes of the EM waves 2602. The sources 2510 and detectors 2520 can beplaced at any location inside or outside of the applicator on or aroundthe treatment area. One aspect of this embodiment is the verticallyarranged sources 2510 and detectors 2520 at the sides are useful inapplications where the tissue is not flat (elevated or pinched) and thetreatment is being applied on the top of the tissue and/or along thesides of tissue. In this case, EM waves 2601 can pass directly acrossthe thermal profile direction. As a result, as the thermal profilepenetrates deeper into the tissue the lower detectors 2520 of thevertically arranged detectors 2520 can measure the temperature gradientas a function of depth in the tissue.

When the EM waves travel along a banana-shaped pathway, increasing thedistance between a source 2510 and a detector 2520 increases the depthwithin the target material that can be monitored. Placing severaldetectors at different distances from the source provides monitoring ofdifferent layers at different depths of a volume of tissue. In anotherembodiment, EM waves travelling through the medium can be collected by apolarized light detector or via a regular detector. The collectedinformation via a regular detector can be further processed to detectthe effect of temperature changes on polarizing the light.

FIG. 27 shows an embodiment of the non-invasive monitoring system 2500with an arrangement of sources 2510 and detectors 2520 on a curvedapplicator 2550. FIG. 28 shows another embodiment of the non-invasivemonitoring system 2500 with a specific arrangement of sources 2510 anddetectors 2520. As shown in FIG. 28, the vertical sources 2510 anddetectors 2520 can transmit/detect EM waves 2605 along the sides of thetarget material 101. The sources 2510 and detectors 2520 can be switchedon/off or constantly activated. The detectors can be paired only withone or several sources at a time.

In operation, the thermal properties and optical characteristics of amedium vary with temperature, which in turn effects the polarizationangle or/and the direction of the unpolarized/polarized EM waves.Through monitoring the changes in polarization angle or/and thedirection of the polarized EM waves, the temperature distribution insidethe tissue at different depths and locations can be determined. Thepreprocessing of the transmitted EM waves and post processing of thereceived EM waves, along with an appropriate hardware andsource/detector arrangement, enables accurate, real-time determinationof the temperature gradient within a volume of tissue. As a result, thenon-invasive monitoring systems 2500 provide a robust tool to controlheating and cooling therapies.

One application of the non-invasive monitoring system 2500 is to limitthe freezing front in adipose tissue. For example, based on a thicknessof the adipose tissue, cooling is continued until the refraction,extinction, absorption, scattering coefficients, amplitude, time offlight and the phase shift for the received signal becomes constant.Different wavelengths can also be used to monitor different componentsof the tissue like fat, water, and muscle separately. To prevent thecooling front from reaching the non-target areas, the variations in thereceived signal from the non-target areas should remain unchanged duringthe treatment. For example, using a least-mean-square computation, orother computational method such as recursive least square, adaptivefilters, empirical mode decomposition, or blind source separation, thesignals from the detectors 2520 can be processed to determine thetemperature gradient from the epidermal layer through the subcutaneousadipose tissue.

From the foregoing, it will be appreciated that specific embodiments ofthe technology have been described herein for purposes of illustration,but that various modifications may be made without deviating from thedisclosure. Accordingly, the invention is not limited except as by theappended claims. Furthermore, certain aspects of the new technologydescribed in the context of particular embodiments may also be combinedor eliminated in other embodiments. Moreover, although advantagesassociated with certain embodiments of the new technology have beendescribed in the context of those embodiments, other embodiments mayalso exhibit such advantages and not all embodiments need necessarilyexhibit such advantages to fall within the scope of the technology.Accordingly, the disclosure and associated technology can encompassother embodiments not expressly shown or described herein.

EXAMPLES

Those having skill in the art, with the knowledge gained from thepresent technology, will understand that various combinations ofembodiments and features from embodiments are within the scope of thepresent technology. Examples of such combinations, which are notlimiting, are set forth in the following listing of numbered clauses.

1. A thermal management system, comprising:

-   -   a thermoelectric component having a first side configured to be        thermally coupled to a target material and a second side        opposite the first side;    -   a two-phase heat transfer unit thermally coupled to the second        side of the thermoelectric component, the two-phase heat        transfer unit having 1) a phase-transition chamber having an        inlet region and an outlet region, 2) microfeatures in the        phase-transition chamber spaced apart from each other such the        microfeatures induce capillary forces to a working fluid that        drives the working fluid from the inlet region of the        phase-transition chamber to the outlet of the phase-transition        chamber, 3) an inlet through which the working fluid flows into        the two-phase heat transfer unit in a liquid phase, and 4) an        outlet through which at least a portion of the working fluid        flows out of the two-phase heat transfer unit in a vapor phase;        and    -   a controller configured to operate the thermoelectric component        and the two-phase heat transfer unit such that the two-phase        heat transfer unit cools the second side of the thermoelectric        component to a first temperature and the thermoelectric        component changes the temperature of the target material to a        second temperature within 0.5-20 seconds, and wherein the second        temperature is +/−60° C. of the first temperature.

2. The system of clause 1 wherein the contact member, thermoelectriccomponent, and the two-phase heat transfer unit together have a heightmeasured along the direction of heat flow from the contact memberthrough the thermoelectric component of 2 mm to 25 mm.

3. The system of any of clauses 1 and 2 wherein the controller isconfigured to set the two-phase heat transfer unit to a firsttemperature of 5° C. to −20° C. at the second side of the thermoelectricunit, and the controller is configured to operate the thermoelectricunit to heat the contact member to a second temperature of 20° C. to 40°C. in 1-10 seconds.

4. The system of any of clauses 1-3 wherein the two-phase heat transferunit has a thickness measured in the direction of the heat flow from thethermoelectric component of 3 mm to 8 mm.

5. The system of any of clauses 1-4 wherein the microfeatures are spacedapart from each other by 10 microns to 1,000 microns.

6. The system of clause 5 wherein the microfeatures are channels definedby walls extending from the inlet region to the outlet region of thephase-transition chamber.

7. The system of clause 5 wherein the microfeatures are pins in thephase-transition chamber.

8. The system of any of clauses 1-7 wherein the microfeatures are spacedapart from each other by 10 microns to 250 microns.

9. The system of any of clauses 1-8 wherein:

-   -   the thermoelectric component comprises a first Peltier module;    -   the system further comprises a second Peltier module positioned        laterally of the first Peltier module;    -   the phase-transitions chamber of the two-phase heat transfer        unit comprises a first phase-transition chamber; and    -   the two-phase heat transfer unit further comprises a second        phase-transition chamber positioned laterally of the first        phase-transition chamber, and the first phase-transition chamber        is aligned with the first Peltier module and the second        phase-transition chamber is aligned with the second Peltier        module.

10. The system of clause 9 wherein the controller is configured to setthe two-phase heat transfer unit to a first temperature of 5° C. to −20°C. at the second side of the thermoelectric unit, and the controller isconfigured to operate the thermoelectric unit to heat the contact memberto a second temperature of 10° C. to 40° C. in 1-10 seconds.

11. The system of any of clauses 9 and 10 wherein the two-phase heattransfer unit has a thickness measured in the direction of the heat flowfrom the thermoelectric component of 2 mm to 8 mm.

12. The system of any of clauses 9-11 wherein the microfeatures arespaced apart from each other by 10 microns to 1,000 microns.

13. The system of clause 12 wherein the microfeatures are channelsdefined by walls extending from the inlet region to the outlet region ofthe phase-transition chamber.

14. The system of clause 12 wherein the microfeatures are pins in thephase-transition chamber.

15. The system of any of clauses 9-14 wherein the microfeatures arespaced apart from each other by 10 microns to 250 microns.

16. The system of any of clauses 9-15 wherein the thermoelectriccomponent has a first volumetric heat capacity and the two-phase heattransfer unit has a second volumetric heat capacity such that secondvolumetric heat capacity is not more than one of 50%, 100%, 150%, 200%,250%, 300%, 400%, or 500% of the first volumetric heat capacity.

17. The system of any of clauses 9-16, further comprising a condenserfluidically coupled to the inlet and outlet of the two-phaseheat-transfer unit, wherein the working fluid is contained within thecondenser and the two-phase heat transfer unit.

18. A method of thermally managing a target material, comprising:

positioning a first side of a thermoelectric component to be thermallycoupled to a target material; cooling a second side of thethermoelectric component to a first temperature using a two-phase heattransfer unit thermally coupled to the second side of the thermoelectriccomponent; and

adjusting electrical current through the thermoelectric component suchthat target material is at second temperature within 0.5-20 seconds, andwherein the second temperature is +/−60° C. of the first temperature.

19. The method of clause 18 wherein the thermoelectric component and thetwo-phase heat transfer unit together have a height measured along thedirection of heat flow through the thermoelectric component of 5 mm to25 mm.

20. The method of any of clauses 18 and 19 wherein the first temperatureis 5° C. to −20° C. at the second side of the thermoelectric unit, thesecond temperature is 20° C. to 40° C., and the time to go from thefirst temperature to the second temperature is 1-10 seconds.

21. The method of any of clauses 18-20 wherein the two-phase heattransfer unit has a thickness measured in the direction of the heat flowfrom the thermoelectric component of 3 mm to 8 mm.

22. The method of any of clauses 18-21 wherein the microfeatures arespaced apart from each other by 10 microns to 1,000 microns.

23. The method of any of clauses 18-22 wherein the microfeatures arechannels defined by walls extending from the inlet region to the outletregion of the phase-transition chamber.

24. The method of any of clauses 18-22 wherein the microfeatures arepins in the phase-transition chamber.

25. The system or method of any of clauses 1-24, further comprising anon-invasive monitoring system having a source that transmits an energyto the target material and a detector that detects a component of theenergy transmitted to the target material by the source, and wherein atemperature gradient in the target material is determined by informationfrom the detector.

26. The system or method of any of clauses 1-26 wherein the source is alight source and the detector is a light detector.

27. A device for treating tissue of a person, comprising:

-   -   a tissue heating module configured to heat target tissue to a        therapy temperature; and    -   a thermal management system including—        -   (a) a contact plate having a high thermal conductivity;        -   (b) a thermoelectric component having a first side            configured to be thermally coupled to the contact plate and            a second side opposite the first side;        -   (c) a two-phase heat transfer unit thermally coupled to the            second side of the thermoelectric component, the two-phase            heat transfer unit having 1) a phase-transition chamber            having an inlet region and an outlet region, 2)            microfeatures in the phase-transition chamber spaced apart            from each other such the microfeatures induce capillary            forces to a working fluid that drives the working fluid from            the inlet region of the phase-transition chamber to the            outlet of the phase-transition chamber, 3) an inlet through            which the working fluid flows into the two-phase heat            transfer unit in a liquid phase, and 4) an outlet through            which at least a portion of the working fluid flows out of            the two-phase heat transfer unit in a vapor phase; and        -   (d) a controller configured to operate the thermoelectric            component and the two-phase heat transfer unit such that the            two-phase heat transfer unit cools the second side of the            thermoelectric component to a first temperature and the            thermoelectric component changes the temperature of the            contact plate to a second temperature within 0.5-20 seconds,            and wherein the second temperature is +/−60° C. of the first            temperature.

28. The device of clause 27, wherein the tissue heating module comprisesa laser configured to heat the target tissue to the therapy temperaturewhile the contact plate cools adjacent tissue.

29. The device of any of clauses 27 and 28, further comprising anon-invasive monitoring system having a source that transmits an energyto the target material and a detector that detects a component of theenergy transmitted to the target material by the source, and wherein atemperature gradient in the target material is determined by informationfrom the detector.

30. The device of clause 29 wherein the source is a light source and thedetector is a light detector.

31. A device for cooling tissue of a person, comprising:

-   -   a contact plate having a high thermal conductivity;    -   a thermoelectric component having a first side configured to be        thermally coupled to the contact plate and a second side        opposite the first side;    -   a two-phase heat transfer unit thermally coupled to the second        side of the thermoelectric component, the two-phase heat        transfer unit having 1) a phase-transition chamber having an        inlet region and an outlet region, 2) microfeatures in the        phase-transition chamber spaced apart from each other such the        microfeatures induce capillary forces to a working fluid that        drives the working fluid from the inlet region of the        phase-transition chamber to the outlet of the phase-transition        chamber, 3) an inlet through which the working fluid flows into        the two-phase heat transfer unit in a liquid phase, and 4) an        outlet through which at least a portion of the working fluid        flows out of the two-phase heat transfer unit in a vapor phase;        and    -   a controller configured to operate the thermoelectric component        and the two-phase heat transfer unit such that the two-phase        heat transfer unit cools the second side of the thermoelectric        component to a first temperature and the thermoelectric        component changes the temperature of the contact plate to a        second temperature within 0.5-20 seconds, and wherein the second        temperature is +/−60° C. of the first temperature.

32. The device of clause 31, further comprising a non-invasivemonitoring system having a source that transmits an energy to the targetmaterial and a detector that detects a component of the energytransmitted to the target material by the source, and wherein atemperature gradient in the target material is determined by informationfrom the detector.

33. The device of clause 32 wherein the source is a light source and thedetector is a light detector.

34. A semiconductor device, comprising:

-   -   a semiconductor component having integrated circuity; and    -   a thermal management system including—        -   (a) a thermoelectric component having a first side            configured to be thermally coupled to the semiconductor            component and a second side opposite the first side;        -   (b) a two-phase heat transfer unit thermally coupled to the            second side of the thermoelectric component, the two-phase            heat transfer unit having 1) a phase-transition chamber            having an inlet region and an outlet region, 2)            microfeatures in the phase-transition chamber spaced apart            from each other such the microfeatures induce capillary            forces to a working fluid that drives the working fluid from            the inlet region of the phase-transition chamber to the            outlet of the phase-transition chamber, 3) an inlet through            which the working fluid flows into the two-phase heat            transfer unit in a liquid phase, and 4) an outlet through            which at least a portion of the working fluid flows out of            the two-phase heat transfer unit in a vapor phase; and        -   (c) a controller configured to operate the thermoelectric            component and the two-phase heat transfer unit such that the            two-phase heat transfer unit cools the second side of the            thermoelectric component to a first temperature and the            thermoelectric component changes the temperature of the            semiconductor component to second temperature.

35. The semiconductor device of clause 34 wherein the semiconductorcomponent is a controller.

36. The semiconductor device of clause 34 wherein the semiconductorcomponent is a memory device.

37. The semiconductor device of clause 34 wherein semiconductorcomponent is in a server

38. A method for altering the temperature of tissue of a patientcomprising

-   -   (a) thermally contacting a device comprising a thermoelectric        component to the outer surface of a first tissue target at a        first temperature T₁, wherein a heat-transfer unit thermally        contacts the thermoelectric component,    -   (b) activating current through the thermoelectric component in a        first direction to cause cooling of the outer surface of the        first tissue target from the first temperature T₁ to between        about 8° C. to about −15° C. in about 2 to 4 seconds, wherein a        heat-transfer unit removes heat flux generated by the        thermoelectric component to maintain the thermoelectric        component at an operating temperature of at least below 50° C.,    -   (c) activating current through the thermoelectric component in a        second direction opposite the first direction to cause heating        of the outer surface of the first tissue target from between        about 8° C. to about −15° C. to at least about 20° C. in about 1        to about 3 seconds.

39. The method of clause 38 wherein the first tissue target isirradiated with laser light or impacted with a needle after step (b) andbefore step (c).

40. The method of clause 38 wherein the first tissue target isirradiated with laser light after step (b) and before step (c) while thedevice remains in contact with the first tissue target.

41. The method of clause 38 wherein the first tissue target is impactedwith a needle after step (b) and before step (c) while the deviceremains in contact with the first tissue target.

42. The method of clause 38 wherein the heat-transfer unit is atwo-phase heat evaporative transfer device.

43. The method of clause 38 wherein the heat-transfer unit is atwo-phase evaporative heat transfer device including an evaporativesystem comprising a plurality of walls extending downwardly from a baseinto a reservoir of evaporative fluid.

44. The method of clause 38 wherein the heat-transfer unit is atwo-phase evaporative heat transfer device that has a condenser unitoperatively connected thereto to receive vapor from the two-phaseevaporative heat transfer device and to condense the vapor intoevaporative fluid.

45. The method of clause 38 wherein the heat-transfer unit is atwo-phase heat evaporative heat transfer device connected to inflow andoutflow conduits for the passage of evaporative fluid therethrough.

46. The method of clause 38 wherein in step (b) activating currentthrough the thermoelectric component in a first direction causes coolingof the outer surface of the first tissue target from the firsttemperature T₁ to between about 8° C. to about −2° C. in about 3seconds.

47. The method of clause 38 wherein in step (b) activating currentthrough the thermoelectric component in a first direction causes coolingof the outer surface of the first tissue target from the firsttemperature T₁ to between about 4° C. to about −2° C. in about 2 to 4seconds.

48. The method of clause 38 wherein in step (b) activating currentthrough the thermoelectric component in a first direction causes coolingof the outer surface of the first tissue target from the firsttemperature T₁ to between about 4° C. to about −2° C. in about 3seconds.

49. The method of clause 38 wherein in step (c) activating currentthrough the thermoelectric component in a second direction opposite thefirst direction causes heating of the outer surface of the first tissuetarget from between about 8° C. to about −2° C. to at least about 20° C.in about 2 seconds.

50. The method of clause 38 wherein the device includes a transparentmaterial and laser light is transmitted through the transparent materialto the first tissue target surface to treat the first tissue target.

51. The method of clause 38 wherein the device includes one or morechannels through the device through which laser light is transmitted tothe first tissue target surface to treat the first tissue target.

52. The method of clause 38 wherein the device includes one or morechannels through the device through which one or more needles aretransmitted to impact the first tissue target surface to treat the firsttissue target.

53. The method of clause 38 wherein the device is attached to a handheldlaser emitting device in a manner to receive laser light from thehandheld laser emitting device.

54. The method of clause 38 further comprising thermally contacting thedevice to the outer surface of a second tissue target and repeatingsteps (a) to (c).

55. The method of clause 38 further comprising repeating steps (a) to(c) upon a plurality of target tissues in series.

56. The method of clause 38 wherein the device includes a plurality ofthermoelectric components connected electrically in series and thermallyin parallel.

57. The method of clause 38 wherein the device includes a plurality ofthermoelectric components connected electrically in series and thermallyin parallel and wherein each thermoelectric component has an associatedmicrochannel evaporative structure positioned adjacent thereto to removeheat from the thermoelectric component.

58. The method of clause 38 wherein the thermoelectric component iselectrically connected to a programmable power source.

59. The method of clause 38 wherein the device includes a plurality ofthermoelectric components connected electrically in series and thermallyin parallel and wherein the plurality of thermoelectric components iselectrically connected to as programmable power source.

What is claimed is:
 1. A thermal management system, comprising: athermoelectric component having a first side configured to be thermallycoupled to a target material and a second side opposite the first side;a two-phase heat transfer unit thermally coupled to the second side ofthe thermoelectric component, the two-phase heat transfer unit having 1)a phase-transition chamber having an inlet region and an outlet region,2) microfeatures in the phase-transition chamber spaced apart from eachother such the microfeatures induce capillary forces to a working fluidthat drives the working fluid from the inlet region of thephase-transition chamber to the outlet of the phase-transition chamber,3) an inlet through which the working fluid flows into the two-phaseheat transfer unit in a liquid phase, and 4) an outlet through which atleast a portion of the working fluid flows out of the two-phase heattransfer unit in a vapor phase; and a controller configured to operatethe thermoelectric component and the two-phase heat transfer unit suchthat the two-phase heat transfer unit cools the second side of thethermoelectric component to a first temperature and the thermoelectriccomponent changes the temperature of the target material to a secondtemperature within 0.5-20 seconds, and wherein the second temperature is+/−60° C. of the first temperature.
 2. The system of claim 1 wherein thecontact member, thermoelectric component, and the two-phase heattransfer unit together have a height measured along the direction ofheat flow from the contact member through the thermoelectric componentof 2 mm to 25 mm.
 3. The system of claim 2 wherein the controller isconfigured to set the two-phase heat transfer unit to a firsttemperature of 5° C. to −20° C. at the second side of the thermoelectricunit, and the controller is configured to operate the thermoelectricunit to heat the contact member to a second temperature of 20° C. to 40°C. in 1-10 seconds.
 4. The system of claim 2 wherein the two-phase heattransfer unit has a thickness measured in the direction of the heat flowfrom the thermoelectric component of 3 mm to 8 mm.
 5. The system ofclaim 2 wherein the microfeatures are spaced apart from each other by 10microns to 1,000 microns.
 6. The system of claim 5 wherein themicrofeatures are channels defined by walls extending from the inletregion to the outlet region of the phase-transition chamber.
 7. Thesystem of claim 5 wherein the microfeatures are pins in thephase-transition chamber.
 8. The system of claim 2 wherein themicrofeatures are spaced apart from each other by 10 microns to 250microns.
 9. The system of claim 1 wherein: the thermoelectric componentcomprises a first Peltier module; the system further comprises a secondPeltier module positioned laterally of the first Peltier module; thephase-transitions chamber of the two-phase heat transfer unit comprisesa first phase-transition chamber; and the two-phase heat transfer unitfurther comprises a second phase-transition chamber positioned laterallyof the first phase-transition chamber, and the first phase-transitionchamber is aligned with the first Peltier module and the secondphase-transition chamber is aligned with the second Peltier module. 10.The system of claim 9 wherein the controller is configured to set thetwo-phase heat transfer unit to a first temperature of 5° C. to −20° C.at the second side of the thermoelectric unit, and the controller isconfigured to operate the thermoelectric unit to heat the contact memberto a second temperature of 10° C. to 40° C. in 1-10 seconds.
 11. Thesystem of claim 10 wherein the two-phase heat transfer unit has athickness measured in the direction of the heat flow from thethermoelectric component of 2 mm to 8 mm.
 12. The system of claim 10wherein the microfeatures are spaced apart from each other by 10 micronsto 1,000 microns.
 13. The system of claim 12 wherein the microfeaturesare channels defined by walls extending from the inlet region to theoutlet region of the phase-transition chamber.
 14. The system of claim12 wherein the microfeatures are pins in the phase-transition chamber.15. The system of claim 10 wherein the microfeatures are spaced apartfrom each other by 10 microns to 250 microns.
 16. The system of claim 1wherein the thermoelectric component has a first volumetric heatcapacity and the two-phase heat transfer unit has a second volumetricheat capacity such that second volumetric heat capacity is not more thanone of 50%, 100%, 150%, 200%, 250%, 300%, 400%, or 500% of the firstvolumetric heat capacity.
 17. The system of claim 1, further comprisinga condenser fluidically coupled to the inlet and outlet of the two-phaseheat-transfer unit, wherein the working fluid is contained within thecondenser and the two-phase heat transfer unit.
 18. The system of claim1, further comprising a non-invasive monitoring system having a sourcethat transmits an energy to the target material and a detector thatdetects a component of the energy transmitted to the target material bythe source, and wherein a temperature gradient in the target material isdetermined by information from the detector.
 19. The system of claim 18wherein the source is a light source and the detector is a lightdetector.
 20. A method of thermally managing a target material,comprising: positioning a first side of a thermoelectric component to bethermally coupled to a target material; cooling a second side of thethermoelectric component to a first temperature using a two-phase heattransfer unit thermally coupled to the second side of the thermoelectriccomponent; and adjusting electrical current through the thermoelectriccomponent such that target material is at second temperature within0.5-20 seconds, and wherein the second temperature is +/−60° C. of thefirst temperature.
 21. The method of claim 20 wherein the thermoelectriccomponent and the two-phase heat transfer unit together have a heightmeasured along the direction of heat flow through the thermoelectriccomponent of 2 mm to 25 mm.
 22. The method of claim 21 wherein the firsttemperature is 5° C. to −20° C. at the second side of the thermoelectricunit, the second temperature is 20° C. to 40° C., and the time to gofrom the first temperature to the second temperature is 1-10 seconds.23. The method of claim 22 wherein the two-phase heat transfer unit hasa thickness measured in the direction of the heat flow from thethermoelectric component of 2 mm to 8 mm.
 24. The method of claim 22wherein the microfeatures are spaced apart from each other by 10 micronsto 1,000 microns.
 25. The method of claim 24 wherein the microfeaturesare channels defined by walls extending from the inlet region to theoutlet region of the phase-transition chamber.
 26. The method of claim24 wherein the microfeatures are pins in the phase-transition chamber.27. A device for treating tissue of a person, comprising: a tissueheating module configured to heat target tissue to a therapytemperature; and a thermal management system including— (a) a contactplate having a high thermal conductivity; (b) a thermoelectric componenthaving a first side configured to be thermally coupled to the contactplate and a second side opposite the first side; (c) a two-phase heattransfer unit thermally coupled to the second side of the thermoelectriccomponent, the two-phase heat transfer unit having 1) a phase-transitionchamber having an inlet region and an outlet region, 2) microfeatures inthe phase-transition chamber spaced apart from each other such themicrofeatures induce capillary forces to a working fluid that drives theworking fluid from the inlet region of the phase-transition chamber tothe outlet of the phase-transition chamber, 3) an inlet through whichthe working fluid flows into the two-phase heat transfer unit in aliquid phase, and 4) an outlet through which at least a portion of theworking fluid flows out of the two-phase heat transfer unit in a vaporphase; and (d) a controller configured to operate the thermoelectriccomponent and the two-phase heat transfer unit such that the two-phaseheat transfer unit cools the second side of the thermoelectric componentto a first temperature and the thermoelectric component changes thetemperature of the contact plate to a second temperature within 0.5-20seconds, and wherein the second temperature is +/−60° C. of the firsttemperature.
 28. The device of claim 27, wherein the tissue heatingmodule comprises a laser configured to heat the target tissue to thetherapy temperature while the contact plate cools adjacent tissue. 29.The device of claim 27, further comprising a non-invasive monitoringsystem having a source that transmits an energy to the target materialand a detector that detects a component of the energy transmitted to thetarget material by the source, and wherein a temperature gradient in thetarget material is determined by information from the detector.
 30. Thesystem of claim 29 wherein the source is a light source and the detectoris a light detector.
 31. A device for cooling tissue of a person,comprising: a contact plate having a high thermal conductivity; athermoelectric component having a first side configured to be thermallycoupled to the contact plate and a second side opposite the first side;a two-phase heat transfer unit thermally coupled to the second side ofthe thermoelectric component, the two-phase heat transfer unit having 1)a phase-transition chamber having an inlet region and an outlet region,2) microfeatures in the phase-transition chamber spaced apart from eachother such the microfeatures induce capillary forces to a working fluidthat drives the working fluid from the inlet region of thephase-transition chamber to the outlet of the phase-transition chamber,3) an inlet through which the working fluid flows into the two-phaseheat transfer unit in a liquid phase, and 4) an outlet through which atleast a portion of the working fluid flows out of the two-phase heattransfer unit in a vapor phase; and a controller configured to operatethe thermoelectric component and the two-phase heat transfer unit suchthat the two-phase heat transfer unit cools the second side of thethermoelectric component to a first temperature and the thermoelectriccomponent changes the temperature of the contact plate to a secondtemperature within 0.5-20 seconds, and wherein the second temperature is+/−60° C. of the first temperature.
 32. The device of claim 31, furthercomprising a non-invasive monitoring system having a source thattransmits an energy to the target material and a detector that detects acomponent of the energy transmitted to the target material by thesource, and wherein a temperature gradient in the target material isdetermined by information from the detector.
 33. The system of claim 32wherein the source is a light source and the detector is a lightdetector.
 34. A semiconductor device, comprising: a semiconductorcomponent having integrated circuity; and a thermal management systemincluding— (a) a thermoelectric component having a first side configuredto be thermally coupled to the semiconductor component and a second sideopposite the first side; (b) a two-phase heat transfer unit thermallycoupled to the second side of the thermoelectric component, thetwo-phase heat transfer unit having 1) a phase-transition chamber havingan inlet region and an outlet region, 2) microfeatures in thephase-transition chamber spaced apart from each other such themicrofeatures induce capillary forces to a working fluid that drives theworking fluid from the inlet region of the phase-transition chamber tothe outlet of the phase-transition chamber, 3) an inlet through whichthe working fluid flows into the two-phase heat transfer unit in aliquid phase, and 4) an outlet through which at least a portion of theworking fluid flows out of the two-phase heat transfer unit in a vaporphase; and (c) a controller configured to operate the thermoelectriccomponent and the two-phase heat transfer unit such that the two-phaseheat transfer unit cools the second side of the thermoelectric componentto a first temperature and the thermoelectric component changes thetemperature of the semiconductor component to second temperature. 35.The semiconductor device of claim 34 wherein the semiconductor componentis a controller.
 36. The semiconductor device of claim 34 wherein thesemiconductor component is a memory device.
 37. The semiconductor deviceof claim 34 wherein semiconductor component is in a server.
 38. A methodfor altering the temperature of tissue of a patient comprising (a)thermally contacting a device comprising a thermoelectric component tothe outer surface of a first tissue target at a first temperature T₁,wherein a heat-transfer unit thermally contacts the thermoelectriccomponent, (b) activating current through the thermoelectric componentin a first direction to cause cooling of the outer surface of the firsttissue target from the first temperature T₁ to between about 8° C. toabout −15° C. in about 2 to 4 seconds, wherein a heat-transfer unitremoves heat flux generated by the thermoelectric component to maintainthe thermoelectric component at an operating temperature of at leastbelow 50° C., (c) activating current through the thermoelectriccomponent in a second direction opposite the first direction to causeheating of the outer surface of the first tissue target from betweenabout 8° C. to about −15° C. to at least about 20° C. in about 1 toabout 3 seconds.
 39. The method of claim 38 wherein the first tissuetarget is irradiated with laser light or impacted with a needle afteract (b) and before act (c).
 40. The method of claim 38 wherein the firsttissue target is irradiated with laser light after act (b) and beforeact (c) while the device remains in contact with the first tissuetarget.
 41. The method of claim 38 wherein the first tissue target isimpacted with a needle after act (b) and before act (c) while the deviceremains in contact with the first tissue target.
 42. The method of claim38 wherein the heat-transfer unit is a two-phase heat evaporativetransfer device.
 43. The method of claim 38 wherein the heat-transferunit is a two-phase evaporative heat transfer device including anevaporative system comprising a plurality of walls extending downwardlyfrom a base into a reservoir of evaporative fluid.
 44. The method ofclaim 38 wherein the heat-transfer unit is a two-phase evaporative heattransfer device that has a condenser unit operatively connected theretoto receive vapor from the two-phase evaporative heat transfer device andto condense the vapor into evaporative fluid.
 45. The method of claim 38wherein the heat-transfer unit is a two-phase heat evaporative heattransfer device connected to inflow and outflow conduits for the passageof evaporative fluid therethrough.
 46. The method of claim 38 wherein inact (b) activating current through the thermoelectric component in afirst direction causes cooling of the outer surface of the first tissuetarget from the first temperature Ti to between about 8° C. to about −2°C. in about 3 seconds.
 47. The method of claim 38 wherein in act (b)activating current through the thermoelectric component in a firstdirection causes cooling of the outer surface of the first tissue targetfrom the first temperature T₁ to between about 4° C. to about −2° C. inabout 2 to 4 seconds.
 48. The method of claim 38 wherein in act (b)activating current through the thermoelectric component in a firstdirection causes cooling of the outer surface of the first tissue targetfrom the first temperature Ti to between about 4° C. to about −2° C. inabout 3 seconds.
 49. The method of claim 38 wherein in act (c)activating current through the thermoelectric component in a seconddirection opposite the first direction causes heating of the outersurface of the first tissue target from between about 8° C. to about −2°C. to at least about 20° C. in about 2 seconds.
 50. The method of claim38 wherein the device includes a transparent material and laser light istransmitted through the transparent material to the first tissue targetsurface to treat the first tissue target.
 51. The method of claim 38wherein the device includes one or more channels through the devicethrough which laser light is transmitted to the first tissue targetsurface to treat the first tissue target.
 52. The method of claim 38wherein the device includes one or more channels through the devicethrough which one or more needles are transmitted to impact the firsttissue target surface to treat the first tissue target.
 53. The methodof claim 38 wherein the device is attached to a handheld laser emittingdevice in a manner to receive laser light from the handheld laseremitting device.
 54. The method of claim 38 further comprising thermallycontacting the device to the outer surface of a second tissue target andrepeating acts (a) to (c).
 55. The method of claim 38 further comprisingrepeating acts (a) to (c) upon a plurality of target tissues in series.56. The method of claim 38 wherein the device includes a plurality ofthermoelectric components connected electrically in series and thermallyin parallel.
 57. The method of claim 38 wherein the device includes aplurality of thermoelectric components connected electrically in seriesand thermally in parallel and wherein each thermoelectric component hasan associated microchannel evaporative structure positioned adjacentthereto to remove heat from the thermoelectric component.
 58. The methodof claim 38 wherein the thermoelectric component is electricallyconnected to a programmable power source.
 59. The method of claim 38wherein the device includes a plurality of thermoelectric componentsconnected electrically in series and thermally in parallel and whereinthe plurality of thermoelectric components is electrically connected toas programmable power source.